app.build.js

{
  baseUrl: '/path/to/rails_root/tmp/assets',
  dir: '/path/to/rails_root/public/assets',
  modules: [ 
    { name: 'application' }, 
    { name: 'users' } 
  ],
  fileExclusionRegExp: /.?/,
  paths: { 
    d3: 'd3/d3', 
    'd3.time': 'd3/d3.time'
  } 
}