diff --git a/Gemfile b/Gemfile
index b6814db..7bbf738 100644
--- a/Gemfile
+++ b/Gemfile
@@ -76,3 +76,5 @@ group :test do
   gem 'selenium-webdriver'
   gem 'webdrivers'
 end
+
+gem 'devise', '~> 4.9'
diff --git a/Gemfile.lock b/Gemfile.lock
index 7a74f3d..9e6af4b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -69,6 +69,7 @@ GEM
     addressable (2.8.4)
       public_suffix (>= 2.0.2, < 6.0)
     ast (2.4.2)
+    bcrypt (3.1.19)
     bindex (0.8.1)
     bootsnap (1.16.0)
       msgpack (~> 1.2)
@@ -88,6 +89,12 @@ GEM
     debug (1.7.1)
       irb (>= 1.5.0)
       reline (>= 0.3.1)
+    devise (4.9.2)
+      bcrypt (~> 3.0)
+      orm_adapter (~> 0.1)
+      railties (>= 4.1.0)
+      responders
+      warden (~> 1.2.3)
     diff-lcs (1.5.0)
     erubi (1.12.0)
     globalid (1.1.0)
@@ -130,6 +137,7 @@ GEM
     nio4r (2.5.9)
     nokogiri (1.15.2-x64-mingw-ucrt)
       racc (~> 1.4)
+    orm_adapter (0.5.0)
     parallel (1.23.0)
     parser (3.2.2.3)
       ast (~> 2.4.1)
@@ -174,6 +182,9 @@ GEM
     regexp_parser (2.8.1)
     reline (0.3.5)
       io-console (~> 0.5)
+    responders (3.1.0)
+      actionpack (>= 5.2)
+      railties (>= 5.2)
     rexml (3.2.5)
     rspec-core (3.12.2)
       rspec-support (~> 3.12.0)
@@ -230,6 +241,8 @@ GEM
     tzinfo-data (1.2023.3)
       tzinfo (>= 1.0.0)
     unicode-display_width (2.4.2)
+    warden (1.2.9)
+      rack (>= 2.0.9)
     web-console (4.2.0)
       actionview (>= 6.0.0)
       activemodel (>= 6.0.0)
@@ -254,6 +267,7 @@ DEPENDENCIES
   bootsnap
   capybara
   debug
+  devise (~> 4.9)
   importmap-rails
   jbuilder
   pg (~> 1.1)
diff --git a/app/assets/stylesheets/application.css b/app/assets/stylesheets/application.css
index b46953e..f2bd3aa 100644
--- a/app/assets/stylesheets/application.css
+++ b/app/assets/stylesheets/application.css
@@ -53,6 +53,7 @@
 
 a {
   text-decoration: none;
+  color: black;
 }
 
 .user-bio {
@@ -148,6 +149,134 @@ button {
   border-radius: 5px;
 }
 
+/* style the authentification pages */
+.auth_pages {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 1rem;
+  color: black;
+  font-size: large;
+  width: 50vw;
+  margin: 100px auto;
+  padding: 1rem;
+  background-color: #c4ddae;
+  border: 1px solid gray;
+}
+
+form {
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+  gap: 1rem;
+  width: 40vw;
+  margin: auto auto;
+}
+
+form input {
+  width: 30vw;
+  padding: 0.5rem;
+}
+
+.shared {
+  display: flex;
+  flex-direction: column-reverse;
+  gap: 0;
+  width: 30vw;
+  padding-bottom: 0.5rem;
+}
+
+.shared a {
+  color: black !important;
+}
+
+ul {
+  list-style: none;
+}
+
+.actions {
+  border: 1px solid #1e1d1d;
+  border-radius: 5px;
+  box-shadow: 1px 1px 1px 1px #1e1d1d;
+}
+
+.actions input {
+  cursor: pointer;
+  font-size: 16.5px;
+}
+
+.remember_me {
+  display: flex;
+  flex-direction: row;
+  justify-content: flex-start;
+  align-items: stretch;
+  gap: 0.5rem;
+}
+
+.remember_me input {
+  width: 1rem;
+  height: 1rem;
+}
+
+.auth_links {
+  display: flex;
+  flex-direction: row;
+  justify-content: flex-start;
+  align-items: center;
+  gap: 1rem;
+  width: 30vw;
+  margin: auto auto;
+}
+
+.auth_links a {
+  color: blue;
+  padding: 0.5rem;
+  box-shadow: #1e1d1d 1px 1px 1px 1px;
+}
+
+#error_explanation {
+  color: red;
+  font-size: large;
+}
+
+#error_explanation h2 {
+  font-size: large;
+  font-weight: normal;
+}
+
+.cancel_back {
+  display: flex;
+  flex-direction: row;
+  justify-content: space-around;
+  width: 50vw;
+}
+
+.cancel_account {
+  display: flex;
+  flex-direction: row;
+  justify-content: space-between;
+  align-items: center;
+  gap: 1rem;
+}
+
+.cancel_back a {
+  color: rgb(104, 4, 235);
+  font-weight: bold;
+}
+
+.cancel_account .button_to {
+  width: 20vw;
+}
+
+.button_to button,
+.button_to button a {
+  cursor: pointer;
+  padding: 5px;
+  font-size: 15px;
+  color: blue;
+  border: none;
+}
+
 .form-elements {
   display: flex;
   flex-direction: row;
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 1d8dbda..227312a 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -1,5 +1,12 @@
 class ApplicationController < ActionController::Base
-  def current_user
-    @current_user ||= User.first
+  before_action :authenticate_user!
+  before_action :configure_permitted_parameters, if: :devise_controller?
+
+  protected
+
+  def configure_permitted_parameters
+    devise_parameter_sanitizer.permit(:sign_up, keys: %i[name email password password_confirmation])
+    devise_parameter_sanitizer.permit(:account_update,
+                                      keys: %i[name email password password_confirmation current_password])
   end
 end
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 54c7d1c..c3c197c 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -7,6 +7,5 @@ def show
     @user = User.find_by_id(params[:id])
 
     redirect_to users_path if @user.nil?
-    @posts = @user.posts
   end
 end
diff --git a/app/models/user.rb b/app/models/user.rb
index ccab1ee..9605970 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -1,4 +1,8 @@
 class User < ApplicationRecord
+  # Include default devise modules. Others available are:
+  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
+  devise :database_authenticatable, :registerable,
+         :recoverable, :rememberable, :validatable
   has_many :posts, foreign_key: :author_id, dependent: :destroy
   has_many :comments, foreign_key: :user_id, dependent: :destroy
   has_many :likes, foreign_key: :user_id, dependent: :destroy
diff --git a/app/views/devise/confirmations/new.html.erb b/app/views/devise/confirmations/new.html.erb
new file mode 100644
index 0000000..4312792
--- /dev/null
+++ b/app/views/devise/confirmations/new.html.erb
@@ -0,0 +1,21 @@
+<div class='auth_pages'>
+
+  <h2>Resend confirmation instructions</h2>
+
+  <%= form_for(resource, as: resource_name, url: confirmation_path(resource_name), html: { method: :post }) do |f| %>
+
+    <div class="field">
+      <%= f.label :email %><br />
+      <%= f.email_field :email, autofocus: true, autocomplete: "email", value: (resource.pending_reconfirmation? ? resource.unconfirmed_email : resource.email) %>
+    </div>
+
+    <%= render "devise/shared/error_messages", resource: resource %>
+
+    <div class="actions">
+      <%= f.submit "Resend confirmation instructions" %>
+    </div>
+  <% end %>
+
+  <%= render "devise/shared/links" %>
+  
+</div>
diff --git a/app/views/devise/mailer/confirmation_instructions.html.erb b/app/views/devise/mailer/confirmation_instructions.html.erb
new file mode 100644
index 0000000..dc55f64
--- /dev/null
+++ b/app/views/devise/mailer/confirmation_instructions.html.erb
@@ -0,0 +1,5 @@
+<p>Welcome <%= @email %>!</p>
+
+<p>You can confirm your account email through the link below:</p>
+
+<p><%= link_to 'Confirm my account', confirmation_url(@resource, confirmation_token: @token) %></p>
diff --git a/app/views/devise/mailer/email_changed.html.erb b/app/views/devise/mailer/email_changed.html.erb
new file mode 100644
index 0000000..32f4ba8
--- /dev/null
+++ b/app/views/devise/mailer/email_changed.html.erb
@@ -0,0 +1,7 @@
+<p>Hello <%= @email %>!</p>
+
+<% if @resource.try(:unconfirmed_email?) %>
+  <p>We're contacting you to notify you that your email is being changed to <%= @resource.unconfirmed_email %>.</p>
+<% else %>
+  <p>We're contacting you to notify you that your email has been changed to <%= @resource.email %>.</p>
+<% end %>
diff --git a/app/views/devise/mailer/password_change.html.erb b/app/views/devise/mailer/password_change.html.erb
new file mode 100644
index 0000000..b41daf4
--- /dev/null
+++ b/app/views/devise/mailer/password_change.html.erb
@@ -0,0 +1,3 @@
+<p>Hello <%= @resource.email %>!</p>
+
+<p>We're contacting you to notify you that your password has been changed.</p>
diff --git a/app/views/devise/mailer/reset_password_instructions.html.erb b/app/views/devise/mailer/reset_password_instructions.html.erb
new file mode 100644
index 0000000..f667dc1
--- /dev/null
+++ b/app/views/devise/mailer/reset_password_instructions.html.erb
@@ -0,0 +1,8 @@
+<p>Hello <%= @resource.email %>!</p>
+
+<p>Someone has requested a link to change your password. You can do this through the link below.</p>
+
+<p><%= link_to 'Change my password', edit_password_url(@resource, reset_password_token: @token) %></p>
+
+<p>If you didn't request this, please ignore this email.</p>
+<p>Your password won't change until you access the link above and create a new one.</p>
diff --git a/app/views/devise/mailer/unlock_instructions.html.erb b/app/views/devise/mailer/unlock_instructions.html.erb
new file mode 100644
index 0000000..41e148b
--- /dev/null
+++ b/app/views/devise/mailer/unlock_instructions.html.erb
@@ -0,0 +1,7 @@
+<p>Hello <%= @resource.email %>!</p>
+
+<p>Your account has been locked due to an excessive number of unsuccessful sign in attempts.</p>
+
+<p>Click the link below to unlock your account:</p>
+
+<p><%= link_to 'Unlock my account', unlock_url(@resource, unlock_token: @token) %></p>
diff --git a/app/views/devise/passwords/edit.html.erb b/app/views/devise/passwords/edit.html.erb
new file mode 100644
index 0000000..2e695f6
--- /dev/null
+++ b/app/views/devise/passwords/edit.html.erb
@@ -0,0 +1,30 @@
+<div class='auth_pages'>
+
+  <h2>Change your password</h2>
+
+  <%= form_for(resource, as: resource_name, url: password_path(resource_name), html: { method: :put }) do |f| %>
+    <%= f.hidden_field :reset_password_token %>
+
+    <div class="field">
+      <%= f.label :password, "New password" %><br />
+      <% if @minimum_password_length %>
+        <em>(<%= @minimum_password_length %> characters minimum)</em><br />
+      <% end %>
+      <%= f.password_field :password, autofocus: true, autocomplete: "new-password" %>
+    </div>
+
+    <div class="field">
+      <%= f.label :password_confirmation, "Confirm new password" %><br />
+      <%= f.password_field :password_confirmation, autocomplete: "new-password" %>
+    </div>
+
+    <%= render "devise/shared/error_messages", resource: resource %>
+    
+    <div class="actions">
+      <%= f.submit "Change my password" %>
+    </div>
+  <% end %>
+
+  <%= render "devise/shared/links" %>
+
+</div>
\ No newline at end of file
diff --git a/app/views/devise/passwords/new.html.erb b/app/views/devise/passwords/new.html.erb
new file mode 100644
index 0000000..10142aa
--- /dev/null
+++ b/app/views/devise/passwords/new.html.erb
@@ -0,0 +1,20 @@
+<div class='auth_pages'>
+
+  <h2>Forgot your password?</h2>
+
+  <%= form_for(resource, as: resource_name, url: password_path(resource_name), html: { method: :post }) do |f| %>
+
+    <div class="field">
+      <%= f.label :email %><br />
+      <%= f.email_field :email, autofocus: true, autocomplete: "email" %>
+    </div>
+
+    <%= render "devise/shared/error_messages", resource: resource %>
+
+    <div class="actions">
+      <%= f.submit "Send me reset password instructions" %>
+    </div>
+  <% end %>
+
+  <%= render "devise/shared/links" %>
+</div>
diff --git a/app/views/devise/registrations/edit.html.erb b/app/views/devise/registrations/edit.html.erb
new file mode 100644
index 0000000..fba58b7
--- /dev/null
+++ b/app/views/devise/registrations/edit.html.erb
@@ -0,0 +1,50 @@
+<div class='auth_pages'>
+
+  <h2>Edit <%= resource_name.to_s.humanize %></h2>
+
+  <%= form_for(resource, as: resource_name, url: registration_path(resource_name), html: { method: :put }) do |f| %>
+
+    <div class="field">
+      <%= f.label :email %><br />
+      <%= f.email_field :email, autofocus: true, autocomplete: "email" %>
+    </div>
+
+    <% if devise_mapping.confirmable? && resource.pending_reconfirmation? %>
+      <div>Currently waiting confirmation for: <%= resource.unconfirmed_email %></div>
+    <% end %>
+
+    <div class="field">
+      <%= f.label :password %> <i>(leave blank if you don't want to change it)</i><br />
+      <%= f.password_field :password, autocomplete: "new-password" %>
+      <% if @minimum_password_length %>
+        <br />
+        <em><%= @minimum_password_length %> characters minimum</em>
+      <% end %>
+    </div>
+
+    <div class="field">
+      <%= f.label :password_confirmation %><br />
+      <%= f.password_field :password_confirmation, autocomplete: "new-password" %>
+    </div>
+
+    <div class="field">
+      <%= f.label :current_password %> <i>(we need your current password to confirm your changes)</i><br />
+      <%= f.password_field :current_password, autocomplete: "current-password" %>
+    </div>
+
+    <%= render "devise/shared/error_messages", resource: resource %>
+
+    <div class="actions">
+      <%= f.submit "Update" %>
+    </div>
+  <% end %>
+
+  <div class="cancel_back">
+    <div class="cancel_account">Unhappy? 
+      <%= button_to "Cancel my account", registration_path(resource_name), data: { confirm: "Are you sure?", turbo_confirm: "Are you sure?" }, method: :delete %>
+    </div>
+
+    <%= link_to "Back", :back %>
+  </div>
+
+</div>
diff --git a/app/views/devise/registrations/new.html.erb b/app/views/devise/registrations/new.html.erb
new file mode 100644
index 0000000..ac81ff3
--- /dev/null
+++ b/app/views/devise/registrations/new.html.erb
@@ -0,0 +1,39 @@
+<div class='auth_pages'>
+
+  <h2>Sign up</h2>
+
+  <%= form_for(resource, as: resource_name, url: registration_path(resource_name)) do |f| %>
+    
+    <div class="field">
+    <%= f.label :name %><br />
+      <%= f.text_field :name, autofocus: true, placeholder: "Name" %>
+    </div>
+
+    <div class="field">
+      <%= f.label :email %><br />
+      <%= f.email_field :email, autofocus: true, autocomplete: "email" %>
+    </div>
+
+    <div class="field">
+      <%= f.label :password %>
+      <% if @minimum_password_length %>
+      <em>(<%= @minimum_password_length %> characters minimum)</em>
+      <% end %><br />
+      <%= f.password_field :password, autocomplete: "new-password" %>
+    </div>
+
+    <div class="field">
+      <%= f.label :password_confirmation %><br />
+      <%= f.password_field :password_confirmation, autocomplete: "new-password" %>
+    </div>
+
+    <%= render "devise/shared/error_messages", resource: resource %>
+    
+    <div class="actions">
+      <%= f.submit "Sign up" %>
+    </div>
+  <% end %>
+
+  <%= render "devise/shared/links" %>
+
+</div>
diff --git a/app/views/devise/sessions/new.html.erb b/app/views/devise/sessions/new.html.erb
new file mode 100644
index 0000000..2cedc02
--- /dev/null
+++ b/app/views/devise/sessions/new.html.erb
@@ -0,0 +1,32 @@
+<div class="auth_pages">
+  <h2>Log in</h2>
+
+  <%= form_for(resource, as: resource_name, url: session_path(resource_name)) do |f| %>
+    <div class="field">
+      <%= f.label :email %><br />
+      <%= f.email_field :email, autofocus: true, autocomplete: "email" %>
+    </div>
+
+    <div class="field">
+      <%= f.label :password %><br />
+      <%= f.password_field :password, autocomplete: "current-password" %>
+    </div>
+
+    <% if devise_mapping.rememberable? %>
+      <div class="remember_me">
+        <%= f.check_box :remember_me %>
+        <%= f.label :remember_me %>
+      </div>
+    <% end %>
+
+    <% if alert %>
+      <p style="color: red" class="alert"><%= alert %></p>
+    <% end %>
+    
+    <div class="actions">
+      <%= f.submit "Log in" %>
+    </div>
+  <% end %>
+
+  <%= render "devise/shared/links" %>
+</div>
diff --git a/app/views/devise/shared/_error_messages.html.erb b/app/views/devise/shared/_error_messages.html.erb
new file mode 100644
index 0000000..cabfe30
--- /dev/null
+++ b/app/views/devise/shared/_error_messages.html.erb
@@ -0,0 +1,15 @@
+<% if resource.errors.any? %>
+  <div id="error_explanation" data-turbo-cache="false">
+    <h2>
+      <%= I18n.t("errors.messages.not_saved",
+                 count: resource.errors.count,
+                 resource: resource.class.model_name.human.downcase)
+       %>
+    </h2>
+    <ul>
+      <% resource.errors.full_messages.each do |message| %>
+        <li><%= message %></li>
+      <% end %>
+    </ul>
+  </div>
+<% end %>
diff --git a/app/views/devise/shared/_links.html.erb b/app/views/devise/shared/_links.html.erb
new file mode 100644
index 0000000..d7f9526
--- /dev/null
+++ b/app/views/devise/shared/_links.html.erb
@@ -0,0 +1,28 @@
+<div class="auth_links">
+  <%- if controller_name != 'sessions' %>
+    <%= link_to "Log in", new_session_path(resource_name) %><br />
+  <% end %>
+
+  <%- if devise_mapping.registerable? && controller_name != 'registrations' %>
+    <%= link_to "Sign up", new_registration_path(resource_name) %><br />
+  <% end %>
+
+  <%- if devise_mapping.recoverable? && controller_name != 'passwords' && controller_name != 'registrations' %>
+    <%= link_to "Forgot your password?", new_password_path(resource_name) %><br />
+  <% end %>
+
+  <%- if devise_mapping.confirmable? && controller_name != 'confirmations' %>
+    <%= link_to "Didn't receive confirmation instructions?", new_confirmation_path(resource_name) %><br />
+  <% end %>
+
+  <%- if devise_mapping.lockable? && resource_class.unlock_strategy_enabled?(:email) && controller_name != 'unlocks' %>
+    <%= link_to "Didn't receive unlock instructions?", new_unlock_path(resource_name) %><br />
+  <% end %>
+
+  <%- if devise_mapping.omniauthable? %>
+    <%- resource_class.omniauth_providers.each do |provider| %>
+      <%= button_to "Sign in with #{OmniAuth::Utils.camelize(provider)}", omniauth_authorize_path(resource_name, provider), data: { turbo: false } %><br />
+    <% end %>
+  <% end %>
+
+</div>
\ No newline at end of file
diff --git a/app/views/devise/unlocks/new.html.erb b/app/views/devise/unlocks/new.html.erb
new file mode 100644
index 0000000..ffc34de
--- /dev/null
+++ b/app/views/devise/unlocks/new.html.erb
@@ -0,0 +1,16 @@
+<h2>Resend unlock instructions</h2>
+
+<%= form_for(resource, as: resource_name, url: unlock_path(resource_name), html: { method: :post }) do |f| %>
+  <%= render "devise/shared/error_messages", resource: resource %>
+
+  <div class="field">
+    <%= f.label :email %><br />
+    <%= f.email_field :email, autofocus: true, autocomplete: "email" %>
+  </div>
+
+  <div class="actions">
+    <%= f.submit "Resend unlock instructions" %>
+  </div>
+<% end %>
+
+<%= render "devise/shared/links" %>
diff --git a/app/views/layouts/application.html.erb b/app/views/layouts/application.html.erb
index 8b5b099..5fd34af 100644
--- a/app/views/layouts/application.html.erb
+++ b/app/views/layouts/application.html.erb
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
   <head>
-    <title>RailsBlogApp</title>
+    <title>Rails Blog App</title>
     <meta name="viewport" content="width=device-width,initial-scale=1">
     <%= csrf_meta_tags %>
     <%= csp_meta_tag %>
@@ -11,6 +11,19 @@
   </head>
 
   <body>
+    <p class="navbar-text float-right">
+    <% if user_signed_in? %>
+      Logged in as <strong><%= current_user.name %></strong>.
+      <%= link_to "Edit profile", edit_user_registration_path, class: "navbar-link" %> |
+      <%= link_to "Logout", destroy_user_session_path, data: { "turbo-method": :delete }, class: "navbar-link"  %>
+    <% end %>
+    </p>
+      <% if notice %>
+      <p style="color: green" class="notice"><%= notice %></p>
+    <% end %>
+
+
     <%= yield %>
+
   </body>
-</html>
+</html>
\ No newline at end of file
diff --git a/config/environments/development.rb b/config/environments/development.rb
index d2411fe..3d3c56b 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -41,6 +41,9 @@
 
   config.action_mailer.perform_caching = false
 
+  #config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
+  config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
+
   # Print deprecation notices to the Rails logger.
   config.active_support.deprecation = :log
 
diff --git a/config/initializers/devise.rb b/config/initializers/devise.rb
new file mode 100644
index 0000000..6916f65
--- /dev/null
+++ b/config/initializers/devise.rb
@@ -0,0 +1,313 @@
+# frozen_string_literal: true
+
+# Assuming you have not yet modified this file, each configuration option below
+# is set to its default value. Note that some are commented out while others
+# are not: uncommented lines are intended to protect your configuration from
+# breaking changes in upgrades (i.e., in the event that future versions of
+# Devise change the default values for those options).
+#
+# Use this hook to configure devise mailer, warden hooks and so forth.
+# Many of these configuration options can be set straight in your model.
+Devise.setup do |config|
+  # The secret key used by Devise. Devise uses this key to generate
+  # random tokens. Changing this key will render invalid all existing
+  # confirmation, reset password and unlock tokens in the database.
+  # Devise will use the `secret_key_base` as its `secret_key`
+  # by default. You can change it below and use your own secret key.
+  # config.secret_key = 'd2256f7472e1aec83818c72efed60283976c9af810d5a1d2783451a20c2220742c30a7f7c542562345d3682c5c0abfc8bef11e952c58cd362cb47f110303dbd8'
+
+  # ==> Controller configuration
+  # Configure the parent class to the devise controllers.
+  # config.parent_controller = 'DeviseController'
+
+  # ==> Mailer Configuration
+  # Configure the e-mail address which will be shown in Devise::Mailer,
+  # note that it will be overwritten if you use your own mailer class
+  # with default "from" parameter.
+  config.mailer_sender = 'please-change-me-at-config-initializers-devise@example.com'
+
+  # Configure the class responsible to send e-mails.
+  # config.mailer = 'Devise::Mailer'
+
+  # Configure the parent class responsible to send e-mails.
+  # config.parent_mailer = 'ActionMailer::Base'
+
+  # ==> ORM configuration
+  # Load and configure the ORM. Supports :active_record (default) and
+  # :mongoid (bson_ext recommended) by default. Other ORMs may be
+  # available as additional gems.
+  require 'devise/orm/active_record'
+
+  # ==> Configuration for any authentication mechanism
+  # Configure which keys are used when authenticating a user. The default is
+  # just :email. You can configure it to use [:username, :subdomain], so for
+  # authenticating a user, both parameters are required. Remember that those
+  # parameters are used only when authenticating and not when retrieving from
+  # session. If you need permissions, you should implement that in a before filter.
+  # You can also supply a hash where the value is a boolean determining whether
+  # or not authentication should be aborted when the value is not present.
+  # config.authentication_keys = [:email]
+
+  # Configure parameters from the request object used for authentication. Each entry
+  # given should be a request method and it will automatically be passed to the
+  # find_for_authentication method and considered in your model lookup. For instance,
+  # if you set :request_keys to [:subdomain], :subdomain will be used on authentication.
+  # The same considerations mentioned for authentication_keys also apply to request_keys.
+  # config.request_keys = []
+
+  # Configure which authentication keys should be case-insensitive.
+  # These keys will be downcased upon creating or modifying a user and when used
+  # to authenticate or find a user. Default is :email.
+  config.case_insensitive_keys = [:email]
+
+  # Configure which authentication keys should have whitespace stripped.
+  # These keys will have whitespace before and after removed upon creating or
+  # modifying a user and when used to authenticate or find a user. Default is :email.
+  config.strip_whitespace_keys = [:email]
+
+  # Tell if authentication through request.params is enabled. True by default.
+  # It can be set to an array that will enable params authentication only for the
+  # given strategies, for example, `config.params_authenticatable = [:database]` will
+  # enable it only for database (email + password) authentication.
+  # config.params_authenticatable = true
+
+  # Tell if authentication through HTTP Auth is enabled. False by default.
+  # It can be set to an array that will enable http authentication only for the
+  # given strategies, for example, `config.http_authenticatable = [:database]` will
+  # enable it only for database authentication.
+  # For API-only applications to support authentication "out-of-the-box", you will likely want to
+  # enable this with :database unless you are using a custom strategy.
+  # The supported strategies are:
+  # :database      = Support basic authentication with authentication key + password
+  # config.http_authenticatable = false
+
+  # If 401 status code should be returned for AJAX requests. True by default.
+  # config.http_authenticatable_on_xhr = true
+
+  # The realm used in Http Basic Authentication. 'Application' by default.
+  # config.http_authentication_realm = 'Application'
+
+  # It will change confirmation, password recovery and other workflows
+  # to behave the same regardless if the e-mail provided was right or wrong.
+  # Does not affect registerable.
+  # config.paranoid = true
+
+  # By default Devise will store the user in session. You can skip storage for
+  # particular strategies by setting this option.
+  # Notice that if you are skipping storage for all authentication paths, you
+  # may want to disable generating routes to Devise's sessions controller by
+  # passing skip: :sessions to `devise_for` in your config/routes.rb
+  config.skip_session_storage = [:http_auth]
+
+  # By default, Devise cleans up the CSRF token on authentication to
+  # avoid CSRF token fixation attacks. This means that, when using AJAX
+  # requests for sign in and sign up, you need to get a new CSRF token
+  # from the server. You can disable this option at your own risk.
+  # config.clean_up_csrf_token_on_authentication = true
+
+  # When false, Devise will not attempt to reload routes on eager load.
+  # This can reduce the time taken to boot the app but if your application
+  # requires the Devise mappings to be loaded during boot time the application
+  # won't boot properly.
+  # config.reload_routes = true
+
+  # ==> Configuration for :database_authenticatable
+  # For bcrypt, this is the cost for hashing the password and defaults to 12. If
+  # using other algorithms, it sets how many times you want the password to be hashed.
+  # The number of stretches used for generating the hashed password are stored
+  # with the hashed password. This allows you to change the stretches without
+  # invalidating existing passwords.
+  #
+  # Limiting the stretches to just one in testing will increase the performance of
+  # your test suite dramatically. However, it is STRONGLY RECOMMENDED to not use
+  # a value less than 10 in other environments. Note that, for bcrypt (the default
+  # algorithm), the cost increases exponentially with the number of stretches (e.g.
+  # a value of 20 is already extremely slow: approx. 60 seconds for 1 calculation).
+  config.stretches = Rails.env.test? ? 1 : 12
+
+  # Set up a pepper to generate the hashed password.
+  # config.pepper = '35141f276cb48bfd2fad72c6190a1356fe001ad52f785bbbb6baac5d8422e8f64b0dd57104d79e6a1996b92587aa4826e8db0e9ed3b99e4ed760860fa93275ce'
+
+  # Send a notification to the original email when the user's email is changed.
+  # config.send_email_changed_notification = false
+
+  # Send a notification email when the user's password is changed.
+  # config.send_password_change_notification = false
+
+  # ==> Configuration for :confirmable
+  # A period that the user is allowed to access the website even without
+  # confirming their account. For instance, if set to 2.days, the user will be
+  # able to access the website for two days without confirming their account,
+  # access will be blocked just in the third day.
+  # You can also set it to nil, which will allow the user to access the website
+  # without confirming their account.
+  # Default is 0.days, meaning the user cannot access the website without
+  # confirming their account.
+  # config.allow_unconfirmed_access_for = 2.days
+
+  # A period that the user is allowed to confirm their account before their
+  # token becomes invalid. For example, if set to 3.days, the user can confirm
+  # their account within 3 days after the mail was sent, but on the fourth day
+  # their account can't be confirmed with the token any more.
+  # Default is nil, meaning there is no restriction on how long a user can take
+  # before confirming their account.
+  # config.confirm_within = 3.days
+
+  # If true, requires any email changes to be confirmed (exactly the same way as
+  # initial account confirmation) to be applied. Requires additional unconfirmed_email
+  # db field (see migrations). Until confirmed, new email is stored in
+  # unconfirmed_email column, and copied to email column on successful confirmation.
+  config.reconfirmable = true
+
+  # Defines which key will be used when confirming an account
+  # config.confirmation_keys = [:email]
+
+  # ==> Configuration for :rememberable
+  # The time the user will be remembered without asking for credentials again.
+  # config.remember_for = 2.weeks
+
+  # Invalidates all the remember me tokens when the user signs out.
+  config.expire_all_remember_me_on_sign_out = true
+
+  # If true, extends the user's remember period when remembered via cookie.
+  # config.extend_remember_period = false
+
+  # Options to be passed to the created cookie. For instance, you can set
+  # secure: true in order to force SSL only cookies.
+  # config.rememberable_options = {}
+
+  # ==> Configuration for :validatable
+  # Range for password length.
+  config.password_length = 6..128
+
+  # Email regex used to validate email formats. It simply asserts that
+  # one (and only one) @ exists in the given string. This is mainly
+  # to give user feedback and not to assert the e-mail validity.
+  config.email_regexp = /\A[^@\s]+@[^@\s]+\z/
+
+  # ==> Configuration for :timeoutable
+  # The time you want to timeout the user session without activity. After this
+  # time the user will be asked for credentials again. Default is 30 minutes.
+  # config.timeout_in = 30.minutes
+
+  # ==> Configuration for :lockable
+  # Defines which strategy will be used to lock an account.
+  # :failed_attempts = Locks an account after a number of failed attempts to sign in.
+  # :none            = No lock strategy. You should handle locking by yourself.
+  # config.lock_strategy = :failed_attempts
+
+  # Defines which key will be used when locking and unlocking an account
+  # config.unlock_keys = [:email]
+
+  # Defines which strategy will be used to unlock an account.
+  # :email = Sends an unlock link to the user email
+  # :time  = Re-enables login after a certain amount of time (see :unlock_in below)
+  # :both  = Enables both strategies
+  # :none  = No unlock strategy. You should handle unlocking by yourself.
+  # config.unlock_strategy = :both
+
+  # Number of authentication tries before locking an account if lock_strategy
+  # is failed attempts.
+  # config.maximum_attempts = 20
+
+  # Time interval to unlock the account if :time is enabled as unlock_strategy.
+  # config.unlock_in = 1.hour
+
+  # Warn on the last attempt before the account is locked.
+  # config.last_attempt_warning = true
+
+  # ==> Configuration for :recoverable
+  #
+  # Defines which key will be used when recovering the password for an account
+  # config.reset_password_keys = [:email]
+
+  # Time interval you can reset your password with a reset password key.
+  # Don't put a too small interval or your users won't have the time to
+  # change their passwords.
+  config.reset_password_within = 6.hours
+
+  # When set to false, does not sign a user in automatically after their password is
+  # reset. Defaults to true, so a user is signed in automatically after a reset.
+  # config.sign_in_after_reset_password = true
+
+  # ==> Configuration for :encryptable
+  # Allow you to use another hashing or encryption algorithm besides bcrypt (default).
+  # You can use :sha1, :sha512 or algorithms from others authentication tools as
+  # :clearance_sha1, :authlogic_sha512 (then you should set stretches above to 20
+  # for default behavior) and :restful_authentication_sha1 (then you should set
+  # stretches to 10, and copy REST_AUTH_SITE_KEY to pepper).
+  #
+  # Require the `devise-encryptable` gem when using anything other than bcrypt
+  # config.encryptor = :sha512
+
+  # ==> Scopes configuration
+  # Turn scoped views on. Before rendering "sessions/new", it will first check for
+  # "users/sessions/new". It's turned off by default because it's slower if you
+  # are using only default views.
+  # config.scoped_views = false
+
+  # Configure the default scope given to Warden. By default it's the first
+  # devise role declared in your routes (usually :user).
+  # config.default_scope = :user
+
+  # Set this configuration to false if you want /users/sign_out to sign out
+  # only the current scope. By default, Devise signs out all scopes.
+  # config.sign_out_all_scopes = true
+
+  # ==> Navigation configuration
+  # Lists the formats that should be treated as navigational. Formats like
+  # :html should redirect to the sign in page when the user does not have
+  # access, but formats like :xml or :json, should return 401.
+  #
+  # If you have any extra navigational formats, like :iphone or :mobile, you
+  # should add them to the navigational formats lists.
+  #
+  # The "*/*" below is required to match Internet Explorer requests.
+  # config.navigational_formats = ['*/*', :html, :turbo_stream]
+
+  # The default HTTP method used to sign out a resource. Default is :delete.
+  config.sign_out_via = :delete
+
+  # ==> OmniAuth
+  # Add a new OmniAuth provider. Check the wiki for more information on setting
+  # up on your models and hooks.
+  # config.omniauth :github, 'APP_ID', 'APP_SECRET', scope: 'user,public_repo'
+
+  # ==> Warden configuration
+  # If you want to use other strategies, that are not supported by Devise, or
+  # change the failure app, you can configure them inside the config.warden block.
+  #
+  # config.warden do |manager|
+  #   manager.intercept_401 = false
+  #   manager.default_strategies(scope: :user).unshift :some_external_strategy
+  # end
+
+  # ==> Mountable engine configurations
+  # When using Devise inside an engine, let's call it `MyEngine`, and this engine
+  # is mountable, there are some extra configurations to be taken into account.
+  # The following options are available, assuming the engine is mounted as:
+  #
+  #     mount MyEngine, at: '/my_engine'
+  #
+  # The router that invoked `devise_for`, in the example above, would be:
+  # config.router_name = :my_engine
+  #
+  # When using OmniAuth, Devise cannot automatically set OmniAuth path,
+  # so you need to do it manually. For the users scope, it would be:
+  # config.omniauth_path_prefix = '/my_engine/users/auth'
+
+  # ==> Hotwire/Turbo configuration
+  # When using Devise with Hotwire/Turbo, the http status for error responses
+  # and some redirects must match the following. The default in Devise for existing
+  # apps is `200 OK` and `302 Found respectively`, but new apps are generated with
+  # these new defaults that match Hotwire/Turbo behavior.
+  # Note: These might become the new default in future versions of Devise.
+  config.responder.error_status = :unprocessable_entity
+  config.responder.redirect_status = :see_other
+
+  # ==> Configuration for :registerable
+
+  # When set to false, does not sign a user in automatically after their password is
+  # changed. Defaults to true, so a user is signed in automatically after changing a password.
+  # config.sign_in_after_change_password = true
+end
diff --git a/config/locales/devise.en.yml b/config/locales/devise.en.yml
new file mode 100644
index 0000000..260e1c4
--- /dev/null
+++ b/config/locales/devise.en.yml
@@ -0,0 +1,65 @@
+# Additional translations at https://github.com/heartcombo/devise/wiki/I18n
+
+en:
+  devise:
+    confirmations:
+      confirmed: "Your email address has been successfully confirmed."
+      send_instructions: "You will receive an email with instructions for how to confirm your email address in a few minutes."
+      send_paranoid_instructions: "If your email address exists in our database, you will receive an email with instructions for how to confirm your email address in a few minutes."
+    failure:
+      already_authenticated: "You are already signed in."
+      inactive: "Your account is not activated yet."
+      invalid: "Invalid %{authentication_keys} or password."
+      locked: "Your account is locked."
+      last_attempt: "You have one more attempt before your account is locked."
+      not_found_in_database: "Invalid %{authentication_keys} or password."
+      timeout: "Your session expired. Please sign in again to continue."
+      unauthenticated: "You need to sign in or sign up before continuing."
+      unconfirmed: "You have to confirm your email address before continuing."
+    mailer:
+      confirmation_instructions:
+        subject: "Confirmation instructions"
+      reset_password_instructions:
+        subject: "Reset password instructions"
+      unlock_instructions:
+        subject: "Unlock instructions"
+      email_changed:
+        subject: "Email Changed"
+      password_change:
+        subject: "Password Changed"
+    omniauth_callbacks:
+      failure: "Could not authenticate you from %{kind} because \"%{reason}\"."
+      success: "Successfully authenticated from %{kind} account."
+    passwords:
+      no_token: "You can't access this page without coming from a password reset email. If you do come from a password reset email, please make sure you used the full URL provided."
+      send_instructions: "You will receive an email with instructions on how to reset your password in a few minutes."
+      send_paranoid_instructions: "If your email address exists in our database, you will receive a password recovery link at your email address in a few minutes."
+      updated: "Your password has been changed successfully. You are now signed in."
+      updated_not_active: "Your password has been changed successfully."
+    registrations:
+      destroyed: "Bye! Your account has been successfully cancelled. We hope to see you again soon."
+      signed_up: "Welcome! You have signed up successfully."
+      signed_up_but_inactive: "You have signed up successfully. However, we could not sign you in because your account is not yet activated."
+      signed_up_but_locked: "You have signed up successfully. However, we could not sign you in because your account is locked."
+      signed_up_but_unconfirmed: "A message with a confirmation link has been sent to your email address. Please follow the link to activate your account."
+      update_needs_confirmation: "You updated your account successfully, but we need to verify your new email address. Please check your email and follow the confirmation link to confirm your new email address."
+      updated: "Your account has been updated successfully."
+      updated_but_not_signed_in: "Your account has been updated successfully, but since your password was changed, you need to sign in again."
+    sessions:
+      signed_in: "Signed in successfully."
+      signed_out: "Signed out successfully."
+      already_signed_out: "Signed out successfully."
+    unlocks:
+      send_instructions: "You will receive an email with instructions for how to unlock your account in a few minutes."
+      send_paranoid_instructions: "If your account exists, you will receive an email with instructions for how to unlock it in a few minutes."
+      unlocked: "Your account has been unlocked successfully. Please sign in to continue."
+  errors:
+    messages:
+      already_confirmed: "was already confirmed, please try signing in"
+      confirmation_period_expired: "needs to be confirmed within %{period}, please request a new one"
+      expired: "has expired, please request a new one"
+      not_found: "not found"
+      not_locked: "was not locked"
+      not_saved:
+        one: "1 error prohibited this %{resource} from being saved:"
+        other: "%{count} errors prohibited this %{resource} from being saved:"
diff --git a/config/routes.rb b/config/routes.rb
index 9065499..06779d6 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,4 +1,5 @@
 Rails.application.routes.draw do
+  devise_for :users
   # Define your application routes per the DSL in https://guides.rubyonrails.org/routing.html
 
   # Defines the root path route ("/")
diff --git a/db/migrate/20230712183456_add_devise_to_users.rb b/db/migrate/20230712183456_add_devise_to_users.rb
new file mode 100644
index 0000000..98ed9dc
--- /dev/null
+++ b/db/migrate/20230712183456_add_devise_to_users.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+class AddDeviseToUsers < ActiveRecord::Migration[7.0]
+  def self.up
+    change_table :users do |t|
+      ## Database authenticatable
+      t.string :email,              null: false, default: ""
+      t.string :encrypted_password, null: false, default: ""
+
+      ## Recoverable
+      t.string   :reset_password_token
+      t.datetime :reset_password_sent_at
+
+      ## Rememberable
+      t.datetime :remember_created_at
+
+      ## Trackable
+      # t.integer  :sign_in_count, default: 0, null: false
+      # t.datetime :current_sign_in_at
+      # t.datetime :last_sign_in_at
+      # t.string   :current_sign_in_ip
+      # t.string   :last_sign_in_ip
+
+      ## Confirmable
+      # t.string   :confirmation_token
+      # t.datetime :confirmed_at
+      # t.datetime :confirmation_sent_at
+      # t.string   :unconfirmed_email # Only if using reconfirmable
+
+      ## Lockable
+      # t.integer  :failed_attempts, default: 0, null: false # Only if lock strategy is :failed_attempts
+      # t.string   :unlock_token # Only if unlock strategy is :email or :both
+      # t.datetime :locked_at
+
+
+      # Uncomment below if timestamps were not included in your original model.
+      # t.timestamps null: false
+    end
+
+    add_index :users, :email,                unique: true
+    add_index :users, :reset_password_token, unique: true
+    # add_index :users, :confirmation_token,   unique: true
+    # add_index :users, :unlock_token,         unique: true
+  end
+
+  def self.down
+    # By default, we don't want to make any assumption about how to roll back a migration when your
+    # model already existed. Please edit below which fields you would like to remove in this migration.
+    raise ActiveRecord::IrreversibleMigration
+  end
+end
diff --git a/db/migrate/20230712200436_update_posts_counter_deafult_to_zero_users.rb b/db/migrate/20230712200436_update_posts_counter_deafult_to_zero_users.rb
new file mode 100644
index 0000000..6f5bf75
--- /dev/null
+++ b/db/migrate/20230712200436_update_posts_counter_deafult_to_zero_users.rb
@@ -0,0 +1,5 @@
+class UpdatePostsCounterDeafultToZeroUsers < ActiveRecord::Migration[7.0]
+  def change
+    change_column_default :users, :posts_counter, from: nil, to: 0
+  end
+end
diff --git a/db/migrate/20230712200853_update_likes_counter_deafult_to_zero_posts.rb b/db/migrate/20230712200853_update_likes_counter_deafult_to_zero_posts.rb
new file mode 100644
index 0000000..e501465
--- /dev/null
+++ b/db/migrate/20230712200853_update_likes_counter_deafult_to_zero_posts.rb
@@ -0,0 +1,5 @@
+class UpdateLikesCounterDeafultToZeroPosts < ActiveRecord::Migration[7.0]
+  def change
+    change_column_default :posts, :likes_counter, from: nil, to: 0
+  end
+end
diff --git a/db/migrate/20230712200923_update_comments_counter_deafult_to_zero_posts.rb b/db/migrate/20230712200923_update_comments_counter_deafult_to_zero_posts.rb
new file mode 100644
index 0000000..c1bff4e
--- /dev/null
+++ b/db/migrate/20230712200923_update_comments_counter_deafult_to_zero_posts.rb
@@ -0,0 +1,5 @@
+class UpdateCommentsCounterDeafultToZeroPosts < ActiveRecord::Migration[7.0]
+  def change
+    change_column_default :posts, :comments_counter, from: nil, to: 0
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 3ba0204..1084210 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2023_06_21_002453) do
+ActiveRecord::Schema[7.0].define(version: 2023_07_12_200923) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -37,8 +37,8 @@
     t.integer "author_id"
     t.string "title"
     t.text "text"
-    t.integer "comments_counter"
-    t.integer "likes_counter"
+    t.integer "comments_counter", default: 0
+    t.integer "likes_counter", default: 0
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["author_id"], name: "index_posts_on_author_id"
@@ -48,9 +48,16 @@
     t.string "name"
     t.string "photo"
     t.text "bio"
-    t.integer "posts_counter"
+    t.integer "posts_counter", default: 0
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.string "email", default: "", null: false
+    t.string "encrypted_password", default: "", null: false
+    t.string "reset_password_token"
+    t.datetime "reset_password_sent_at"
+    t.datetime "remember_created_at"
+    t.index ["email"], name: "index_users_on_email", unique: true
+    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
 
   add_foreign_key "comments", "posts"