title: Ruby Gem: Get files in asset pipeline
body: <p>I've developed a plugin ( jQuery ) which I really want to make into a gem. For the gem to work I need three files to be in the asset pipeline of Rails: an image, a javascript file and a css file. </p>
  
  <p>On this moment I've got the gem working, but! I can't get the files in the asset pipeline. If I include them like this:</p>
  
  <pre><code>//= require gem.js
  </code></pre>
  
  <p>Or</p>
  
  <pre><code>//= require gem.css
  </code></pre>
  
  <p>It works, but the files doesn't show up in the asset pipeline and while I can make this work with the css and js file, I can't make this work for the images.</p>
  
  <p>Thereby I really want the files to show up in the asset pipeline ( or at least the image, which is needed to give the plugin extra glance ). On this moment I've done everything I could think off, but it doesn't work..</p>
  
  <p>This is my gemspec:</p>
  
  <pre><code># -*- encoding: utf-8 -*-
  $:.push File.expand_path("../lib", __FILE__)
  require "yellow-text-rails/version"
  
  Gem::Specification.new do |gem|
      # Gem information
      gem.name          = "yellow-text-rails"
      gem.version       = YellowText::Rails::VERSION
      gem.authors       = ["Stefan Vermaas"]
  
      # Project name
      gem.rubyforge_project = "yellow-text-rails" 
  
      gem.files         = `git ls-files`.split("\n")
      gem.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
      gem.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
      gem.require_paths = ["lib"]
  end
  </code></pre>
  
  <p>And I've included this in `lib/yellow-text-rails/yellow-text-rails.rb':</p>
  
  <pre><code>require "yellow-text-rails/version"
  
  module YellowText
      module Rails
          if defined?(::Rails) and ::Rails.version &gt;= "3.1"
                  class Rails::Engine &lt; ::Rails::Engine
              end
          end
      end
  end
  </code></pre>
  
  <p>Hopefully you guys can help me out! Thanks!</p>