Same demo with explicitly mutable property declaration

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  actions: {
    addChannel(name) {
      this.get('model').addObject({ name })
    }
  }
});

application.route.js

import Ember from 'ember';
let { RSVP, A, Object } = Ember;

export default Ember.Route.extend({
  model() {
	  return RSVP.resolve(A([
      Object.create({ name: 'Channel 1' }),
      Object.create({ name: 'Channel 2' })
    ]))
  }
});

application.template.hbs

{{channel-list list=model}}

{{channel-form onSubmit=(action "addChannel")}}

channel-form.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  tagName: 'form',
  name: '',
  
  submit(event) {
    event.preventDefault()
    this.attrs.onSubmit(this.get('name'))
		this.set('name', '')  
	},
});

channel-form.template.hbs

{{input type="text" value=(mut name)}}

channel-list.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  tagName: 'ul'
})

channel-list.template.hbs

{{#each list key="name" as |channel|}}
<li>{{channel.name}}</li>
{{/each}}

twiddle.json

{
  "version": "0.4.16",
  "EmberENV": {
    "FEATURES": {}
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.1.0",
    "ember-data": "2.1.0",
    "ember-template-compiler": "2.1.0"
  }
}