The Grails coffee-grails is a plugin that provides coffee-script support for the asset-pipeline static asset management plugin.
For more information on how to use asset-pipeline, visit here.
Simply create files in your standard assets/javascripts folder with extension .coffee or .js.coffee. You also may require other files by using the following requires syntax at the top of each file:
#= require test
#= require_self
#= require_tree .NOTE: If the command line node coffee command is detected on your system. The application will attempt to use node to compile your javascript instead.