Model array change

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle',
  
  actions: {
    add() {
      this.get('model').pushObject(this.get('model.length') + 1)  
    },
    
    delete() {
      this.get('model').popObject();
    }
  }
});

application.route.js

import Ember from 'ember';

export default Ember.Route.extend({
  model: function() {
    return Ember.A([1, 2, 3]);
  }
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#each model as |record|}}
  {{record}}
{{/each}}
<div>
<button onclick={{action 'delete'}}>Delete entry</button>
<button onclick={{action 'add'}}>Add entry</button>
</div>
<br>
<br>

twiddle.json

{
  "version": "0.5.3",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.3.1/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.3.3/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.2.0/ember-template-compiler.js"
  }
}