New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

controllers.index.js

import Ember from 'ember';

export default Ember.Controller.extend({
  actions: {
    setMetadata(myModel) {
      Ember.set(myModel, 'metadata.foo', 'Clicked!');
    }
  }
});

models.my-model.js

import Model from "ember-data/model";
import attr from "ember-data/attr";
import { belongsTo, hasMany } from "ember-data/relationships";

export default Model.extend({
  title: attr('string'),
  metadata: attr({defaultValue() { return {}; }}),
  createdAt: attr('date', {
    defaultValue() { return new Date(); }
  })
});

routes.index.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
    return Ember.get(this, 'store').createRecord('my-model', { title: 'foo' });
  },
});

templates.application.hbs

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

templates.index.hbs

<br />
{{model.metadata.foo}}
<br />
{{model.createdAt}}
<br />
{{model.title}}
<br />
<button {{action 'setMetadata' model}}>Click me!</button>

twiddle.json

{
  "version": "0.13.0",
  "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"
  }
}