New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  options: ['option 1', 'option 2', 'option 3'],
  selectedOtions: [],
  actions: {
   	select(items) {
      this.set('selectedOptions', items);
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

{{!- this was required to make the page render in twiddle --}}
<div id="ember-basic-dropdown-wormhole"></div>

{{#power-select-multiple
  placeholder="Select"
  options=options
  selected=selectedOptions
  onchange=(action "select")
  as |type|
}}
  {{type}}
{{/power-select-multiple}}

twiddle.json

{
  "version": "0.10.4",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.7.0",
    "ember-data": "2.7.0",
    "ember-template-compiler": "2.7.0"
  },
  "addons": {
    "ember-power-select": "1.0.0-beta.10"
  }
}