A rudimentary example of a grunt-contrib-coffeescript project, with chruby effectively setting the ruby version (where RVM could not). See https://github.com/gruntjs/grunt-contrib-compass/issues/49

config.rb

# Just to show that chruby takes effect.
puts RUBY_VERSION

Gemfile

source "https://rubygems.org"

gem 'compass', '>= 0.12.2'

Gruntfile.coffee

module.exports = (grunt) ->
  grunt.loadNpmTasks 'grunt-contrib-compass'

  grunt.initConfig
    compass:
      dist:
        options:
          config: 'config.rb'
          bundleExec: true

package.json

{
  "name": "temp",
  "version": "0.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "BSD",
  "dependencies": {
    "grunt": "~0.4.2",
    "grunt-contrib-compass": "~0.7.0"
  }
}