promise array with initialized content

application.controller.js

import Ember from 'ember';
var PromiseArray = Ember.ArrayProxy.extend(Ember.PromiseProxyMixin);

export default Ember.Controller.extend({
  appName:'Ember Twiddle',
  p: PromiseArray.create({
    promise: new Ember.RSVP.Promise(function(resolve, reject) {
  setTimeout(function(){
    resolve([1,2,3]);
  }, 3000);
}),
    content: [2,3]
  })
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#each p as |o|}}
{{o}}
{{/each}}
<br>
<br>

twiddle.json

{
  "version": "0.4.11",
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/1.13.11/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember-template-compiler.js"
  }
}