建立自己第一個gem

1. 先要有https://rubygems.org/帳號

2. 安裝環境必要套件
$ gem update --system
$ gem install rubygems-update
Fetching: rubygems-update-2.7.6.gem (100%)
Successfully installed rubygems-update-2.7.6
Parsing documentation for rubygems-update-2.7.6
Installing ri documentation for rubygems-update-2.7.6
Done installing documentation for rubygems-update after 28 seconds
1 gem installed
$ update_rubygems

3. 建立gem資料夾 (voteable_shawn)
$mkdir voteable_shawn
$cd voteable_shawn
$mkdir lib

4. 設定檔
voteable_shawn/voteable_shawn.gemspec
Gem::Specification.new do |s|
  s.name        = 'voteable_shawn'
  s.version     = '0.0.0'
  s.licenses    = ['MIT']
  s.summary     = "This is a voteable gem example!"
  s.description = "The voting gem!"
  s.authors     = ["Shawn"]
  s.email       = 'shawnkuo67@gmail.com'
  s.files       = ["lib/voteable_shawn.rb"]
  s.homepage    = 'https://rubygems.org/gems/example'
  s.metadata    = { "source_code_uri" => "https://github.com/example/example" }
end

voteable_shawn/lib/voteable_shawn.rb
module Voteable
  extend ActiveSupport::Concern

  included do
    has_many :votes, as: :voteable
  end

  def vote_total
    self.vote_up - self.vote_down
  end
  def vote_up
    self.votes.where(vote: true).size
  end
  def vote_down
    self.votes.where(vote: false).size
  end
end

4. 安裝編譯套件
$ gem install gemcutter
Fetching: gemcutter-0.7.1.gem (100%)
********************************************************************************

           Thanks for installing Gemcutter! You can now run:

  gem push        merged into RubyGems 1.3.6
  gem owner       merged into RubyGems 1.3.6
  gem webhook     register urls to be pinged when gems are pushed
  gem yank        remove a specific version of a gem from RubyGemgem.org

********************************************************************************
Successfully installed gemcutter-0.7.1
Parsing documentation for gemcutter-0.7.1
Installing ri documentation for gemcutter-0.7.1
Done installing documentation for gemcutter after 0 seconds
1 gem installed
$ gem list gemcutter

*** LOCAL GEMS ***

gemcutter (0.7.1)
5. 發布gem
$ gem push voteable_shawn-0.0.0.gem

6. Repo:
https://github.com/shawnkaku/voteable_gem.git

7. ##應該改用$ bundle gem voteable_shawn
$ bundle gem voteable_shawn
 create  voteable_shawn/Gemfile
 create  voteable_shawn/Rakefile
 create  voteable_shawn/LICENSE.txt
 create  voteable_shawn/README.md
 create  voteable_shawn/.gitignore
 create  voteable_shawn/voteable_shawn.gemspec
 create  voteable_shawn/lib/voteable_shawn.rb

 create  voteable_shawn/lib/voteable_shawn/version.rb

8. 打包gem
$ cd voteable_shawn/
$ gem build voteable_shawn.gemspec
WARNING:  no homepage specified
WARNING:  open-ended dependency on rake (>= 0, development) is not recommended
  if rake is semantically versioned, use:
    add_development_dependency 'rake', '~> 0'
WARNING:  See http://guides.rubygems.org/specification-reference/ for help
  Successfully built RubyGem
  Name: voteable_shawn
  Version: 0.0.1

  File: voteable_shawn-0.0.1.gem
9. 上傳gem
$ gem push voteable_shawn-0.0.1.gem