New Twiddle

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  versions: Ember.computed('model.versions.[]', function () {
		return this.get('model.versions').slice(1);
  }),
  actions: {
		updateVersions () {
			let modelVersions = this.get('model.versions');
      // SOLUTION: use Ember array methods. regular js array methods don't update observers
    	modelVersions.pop();
    	modelVersions.unshift({
    		version: modelVersions[0].version + 1
  		});
      console.log(this.get('model.versions'));
  	}
  }
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  model () {
		return {
      versions: [{ version: 5 }, { version: 4 }, { version: 3}]
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#each versions as |version|}}
	Version number: {{version.version}}
{{/each}}
<br>
<br>
<button {{action 'updateVersions'}}>Update Versions</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"
  }
}