Disable EmberCLI JS minification

When precompiling assets in production, we ensure that we are not
minifying the JavaScript assets twice.

Duplicating minification can slow down assets precompilation
considerably.

Closes [tricknotes/ember-cli-rails#124][124] and
[tricknotes/ember-cli-rails#123][123].

[123]: tricknotes/ember-cli-rails#123
[124]: tricknotes/ember-cli-rails#124

CHANGELOG.md

@@ -1,4 +1,9 @@
 master
 ------
 
+* Disable EmberCLI minification (closes [thoughtbot/ember-cli-rails#124][124] and
+  [thoughtbot/ember-cli-rails#123][123])
 * Copies `dist/index.html` to `dist/assets/index.html` after a build
+
+[123]: https://github.com/thoughtbot/ember-cli-rails/pull/123
+[124]: https://github.com/thoughtbot/ember-cli-rails/pull/124

index.js

@@ -23,6 +23,7 @@ module.exports = {
 
   included: function(app) {
     app.options.storeConfigInMeta = false;
+    app.options.minifyJS = false;
 
     if (process.env.DISABLE_FINGERPRINTING === 'true') {
       app.options.fingerprint = app.options.fingerprint || {};