http://stackoverflow.com/questions/40432554/how-to-trigger-an-action-using-an-ember-service

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  changeTheme: Ember.inject.service(),
});

services.change-theme.js

import Ember from 'ember';

export default Ember.Service.extend({
  changeBackground() {
    Ember.$('body').toggleClass('bg-color-change');
    alert(' change ');
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<button id="change-theme" class="btn" {{action "changeBackground" target=changeTheme}}>Change Theme</button>
<br>
{{outlet}}
<br>
<br>

twiddle.json

{
  "version": "0.10.6",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.9.0",
    "ember-data": "2.9.0",
    "ember-template-compiler": "2.9.0",
    "ember-testing": "2.9.0"
  },
  "addons": {}
}