各記事にタグを付ける

app/assets/javascripts/taggings.coffee

@@ -0,0 +1,3 @@
+# Place all the behaviors and hooks related to the matching controller here.
+# All this logic will automatically be available in application.js.
+# You can use CoffeeScript in this file: http://coffeescript.org/

app/assets/stylesheets/taggings.css.scss

@@ -0,0 +1,3 @@
+// Place all the styles related to the taggings controller here.
+// They will automatically be included in application.css.
+// You can use Sass (SCSS) here: http://sass-lang.com/

app/controllers/articles_controller.rb

@@ -10,6 +10,7 @@ def index
   # GET /articles/1
   # GET /articles/1.json
   def show
+    @tags = @article.tags.map{|tag| tag.name}
   end
 
   # GET /articles/new

app/controllers/taggings_controller.rb

@@ -0,0 +1,24 @@
+class TaggingsController < ApplicationController
+  def create
+    tags = params[:tag_names].split(',')
+    tag_ids = tags.map do |tag_name|
+      tag = Tag.new
+      tag.name = tag_name
+      tag.save
+      tag.id
+    end
+
+    tag_ids.each do |tag_id|
+      tagging = Tagging.new(tagging_params)
+      tagging.tag_id = tag_id
+      tagging.save
+    end
+
+    redirect_to root_path
+  end
+
+  private 
+  def tagging_params 
+    params.require(:tagging).permit(:article_id)
+  end
+end

app/helpers/taggings_helper.rb

@@ -0,0 +1,2 @@
+module TaggingsHelper
+end

app/models/article.rb

@@ -1,2 +1,4 @@
 class Article < ActiveRecord::Base
+  has_many :taggings
+  has_many :tags, through: :taggings
 end

app/models/tag.rb

@@ -0,0 +1,4 @@
+class Tag < ActiveRecord::Base
+  has_many :taggings
+  has_many :articles, through: :taggings
+end

app/models/tagging.rb

@@ -0,0 +1,4 @@
+class Tagging < ActiveRecord::Base
+  belongs_to :tag
+  belongs_to :article
+end

app/views/articles/show.html.slim

@@ -10,6 +10,18 @@ p
   strong Body:
   = processor.call(@article.body)[:output].to_s.html_safe
 
+p
+  strong Tags:
+  = @tags.join(', ')
+
+= form_for Tagging.new do |f|
+  p
+    |tags:
+    = text_field_tag :tag_names
+
+  = hidden_field :tagging, :article_id, value: @article.id
+  p= f.submit 'Tag Create'
+
 = link_to 'Edit', edit_article_path(@article)
 '|
 = link_to 'Back', articles_path

config/routes.rb

@@ -1,6 +1,7 @@
 Rails.application.routes.draw do
   root 'articles#index'
   resources :articles
+  resources :taggings
 
   # The priority is based upon order of creation: first created -> highest priority.
   # See how all your routes lay out with "rake routes".

db/migrate/20141025042303_create_tags.rb

@@ -0,0 +1,9 @@
+class CreateTags < ActiveRecord::Migration
+  def change
+    create_table :tags do |t|
+      t.string :name
+
+      t.timestamps
+    end
+  end
+end

db/migrate/20141025042749_create_taggings.rb

@@ -0,0 +1,10 @@
+class CreateTaggings < ActiveRecord::Migration
+  def change
+    create_table :taggings do |t|
+      t.references :tag, index: true
+      t.references :article, index: true
+
+      t.timestamps
+    end
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20141024184049) do
+ActiveRecord::Schema.define(version: 20141025042749) do
 
   create_table "articles", force: true do |t|
     t.string   "title"
@@ -20,4 +20,20 @@
     t.datetime "updated_at"
   end
 
+  create_table "taggings", force: true do |t|
+    t.integer  "tag_id"
+    t.integer  "article_id"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+  end
+
+  add_index "taggings", ["article_id"], name: "index_taggings_on_article_id"
+  add_index "taggings", ["tag_id"], name: "index_taggings_on_tag_id"
+
+  create_table "tags", force: true do |t|
+    t.string   "name"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+  end
+
 end

spec/controllers/taggings_controller_spec.rb

@@ -0,0 +1,5 @@
+require 'rails_helper'
+
+RSpec.describe TaggingsController, :type => :controller do
+
+end

spec/fabricators/tag_fabricator.rb

@@ -0,0 +1,3 @@
+Fabricator(:tag) do
+  name "MyString"
+end

spec/fabricators/tagging_fabricator.rb

@@ -0,0 +1,4 @@
+Fabricator(:tagging) do
+  tag     nil
+  article nil
+end

spec/helpers/taggings_helper_spec.rb

@@ -0,0 +1,15 @@
+require 'rails_helper'
+
+# Specs in this file have access to a helper object that includes
+# the TaggingsHelper. For example:
+#
+# describe TaggingsHelper do
+#   describe "string concat" do
+#     it "concats two strings with spaces" do
+#       expect(helper.concat_strings("this","that")).to eq("this that")
+#     end
+#   end
+# end
+RSpec.describe TaggingsHelper, :type => :helper do
+  pending "add some examples to (or delete) #{__FILE__}"
+end

spec/models/tag_spec.rb

@@ -0,0 +1,5 @@
+require 'rails_helper'
+
+RSpec.describe Tag, :type => :model do
+  pending "add some examples to (or delete) #{__FILE__}"
+end

spec/models/tagging_spec.rb

@@ -0,0 +1,5 @@
+require 'rails_helper'
+
+RSpec.describe Tagging, :type => :model do
+  pending "add some examples to (or delete) #{__FILE__}"
+end