ember-cli-rails-routes

Add this to your Gemfile and bundle install

gem 'ember-cli-rails-routes'

In your routes.rb file:

ember_app :foo, scope: :app, path: 'frontend'

This reflects an ember app in the <RAILS_ROOT>/frontend directory that is exposed as /app/foo in the URL.

First, you need to tell Ember to prepend the apps directory so Rails can serve assets from the right Ember app.

Here frontend/ is the same as path from above.

// ember-cli-build.js
var app = new EmberApp(defaults, {
  fingerprint: {
    enabled: true,
    prepend: 'frontend/'
  }
});

Second, tell Ember to treat the app route as the main entry point of the Ember app.

// app/router.js
Router.map(function() {
  this.route('frontend', { path: '/app/foo' }, function() {

  });
});

Notice that using the fingerprint option causes the assets to be fingerprinted even in development, which increases build times. You can get just the prepend behavior and only in development by using the ember-cli-rails-routes addon.

$ ember install ember-cli-rails-routes
$ RAILS_PREPEND=frontend/ ember build

• cd into ember app (test/dummy/frontend)
  • ember build
• cd into dummy rails app (test/dummy)
  • cucumber