title: setting constants when config.assets.initialize_on_precompile is false
body: <p>Deploying on Heroku requires that <code>config.assets.initialize_on_precompile=false</code> in application.rb. From the <a href="http://guides.rubyonrails.org/asset_pipeline.html#precompiling-assets" rel="nofollow">Rails Guide</a> it says that this "partially loads your application". </p>
  
  <p>So I was wondering what the best practices were for setting some constants to be used in compiled assets (e.g. *.js.erb)? With this flag set to false I can't use anything that is set in initailizers. I'm not super clear on what parts of the application are loaded, and how I might be able to set any constants, variables etc before the compilation step is performed. </p>
  
  <p>Thanks!</p>