class Rails < Thor
  desc "checkout VERSION", "checks it out"
  def checkout(version)
    puts "***** checking out rails at #{version} ..."
    Dir.chdir("vendor/rails") do
      `git checkout #{version}`
      `rm Gemfile.lock` if File.exist?('Gemfile.lock')
      puts `bundle show`
    end
  end

  desc "fetch", "update vendor/rails"
  def fetch
    Dir.chdir("vendor/rails") do
      `git fetch`
    end
  end

  desc "use VERSION", "copies the appropriate Gemfile to Gemfile"
  def use(version)
    `cp ./Gemfile-#{version} ./Gemfile` 
    `rm ./Gemfile.lock`
    system "bundle install"
  end
end
