Working Ember Data 1.13 Embedded Records

adapters.post.js

import Ember from 'ember';
import DS from 'ember-data';

const { RSVP } = Ember;

export default DS.RESTAdapter.extend({
  findAll(store, type, sinceToken, snapshotRecordArray) {
    return RSVP.resolve({
      posts: [{
        id: 1,
        author: {
          id: 2,
          name: 'lovelace'
        }
      }]
    });
  },
});

controllers.application.js

import Ember from 'ember';

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

models.author.js

import DS from 'ember-data';

const { attr, belongsTo } = DS;

export default DS.Model.extend({
  name: attr(),
  authorid: attr()
});

models.post.js

import DS from 'ember-data';

const { belongsTo, Model } = DS;

export default Model.extend({
  author: belongsTo('author')
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  model() {
   	return Ember.RSVP.hash({
      posts: this.store.findAll('post')
    });
  }
});

serializers.post.js

import DS from 'ember-data';

const { RESTSerializer, EmbeddedRecordsMixin } = DS;
export default RESTSerializer.extend(
EmbeddedRecordsMixin, 
{
  isNewSerializerAPI: true,
  attrs: {
    'author': { serialize: 'records', deserialize: 'records' }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{#each model.posts as |post|}}
	{{post.author.name}}
{{/each}}
<br>
<br>

twiddle.json

{
  "version": "0.10.6",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.9.0",
    "ember-data": "1.13.11",
    "ember-template-compiler": "2.9.0",
    "ember-testing": "2.9.0"
  },
  "addons": {}
}