add assetLoader block to the build to support rootURL for engines

ui/ember-cli-build.js

@@ -2,13 +2,20 @@
 'use strict';
 
 const EmberApp = require('ember-cli/lib/broccoli/ember-app');
+const config = require('./config/environment')();
 
 const environment = EmberApp.env();
 const isProd = environment === 'production';
 const isTest = environment === 'test';
 
 module.exports = function(defaults) {
  var app = new EmberApp(defaults, {
+ assetLoader: {
+ generateURI: function(filePath) {
+ return `${config.rootURL.replace(/\/$/, '')}${filePath}`;
+ },
+ },
+
  codemirror: {
  modes: ['javascript', 'ruby'],
  keyMaps: ['sublime'],