Watching objects in template

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  init() {
    this._super(...arguments);
    this.thingsByName = {};
  },
  
  actions: {
    push(name) {
      console.log(name);
      this.set(`thingsByName.${name}`, Math.random());
      this.set('inputValue', '');
    }
  }
});

templates.application.hbs

<input type="text" value={{inputValue}} onchange={{action (mut inputValue) value="target.value"}}/>

<br>
<button onclick={{action 'push' inputValue}}>Add To Object</button>

<ul>
{{#each-in thingsByName as |name thing|}}
	<li>{{name}} - {{thing}}</li>
{{/each-in}}
</ul>

twiddle.json

{
  "version": "0.13.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3"
  }
}