gistfile1.rb

      # Returns the path to the rails/init.rb file for the given extension,
      # or nil if no gem provides it.
      def init_path_for_extension(extension)
        return if extension.blank?
        return unless spec = Gem.searcher.find(extension.to_s)
        returning File.join(spec.full_gem_path, 'rails', 'init.rb') do |path|
          return unless File.file?(path)
        end
      end