The matplotlib gem is required to execute sample code but not noted.

[teslur]

Following two gems are required to execute sample code that is written in Usage section of README.md.

gem 'numo-narray'
gem 'matplotlib'

The numo-narray gem might be required because of this issue.
#51

Since this is sample code, I expected that all the required gems would be noted near the code.
How about add a note of required gem near the sample code?

Or, if the charty gem always requires the matplotlib gem to draw graphs, how about include the matplotlib gem as a dependent gem?

Environment

$ uname -a
Darwin xxxxMacBook-Pro.local 18.5.0 Darwin Kernel Version 18.5.0: Mon Mar 11 20:40:32 PDT 2019; root:xnu-4903.251.3~3/RELEASE_X86_64 x86_64

$ ruby --version
ruby 2.6.2p47 (2019-03-13 revision 67232) [x86_64-darwin18]

Executed sample code

$ cat sample_1.rb
require 'bundler/setup'
require 'charty'

charty = Charty::Plotter.new(:pyplot)

bar = charty.bar do
  series [0,1,2,3,4], [10,40,20,90,70], label: "sample1"
  series [0,1,2,3,4], [90,80,70,60,50], label: "sample2"
  series [0,1,2,3,4,5,6,7,8], [50,60,20,30,10, 90, 0, 100, 50], label: "sample3"
  range x: 0..10, y: 1..100
  xlabel 'foo'
  ylabel 'bar'
  title 'bar plot'
end
bar.render("sample_images/bar_pyplot.png")

[mrkn]

@teslur Thank you for your feedback.
The version 0.2.3 I've released now doesn't require numo-narray.
Please use it.