HasMany get lost

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle',
  
  actions: {
    add() {
      console.log('add');
      let provider = this.get('model.firstObject');
      let item = { name: 'Feature X', provider: provider };
      
      this.get('store')
      	.createRecord('feature', item)
      	.save();
     	console.log(provider);
    },
    drop(feature) {
      let provider = this.get('model.firstObject');
      console.log('drop', feature);
      feature.destroyRecord()
      	.then(function(feat) {
          provider.save();
        });
    }
  }
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<span {{action 'add'}}>Add</span>

<br>
<br>
{{#each model as |provider|}}
  {{provider.name}}<br>
  
  {{#each provider.features as |feature|}}
  	- {{feature.name}} - <span {{action 'drop' feature}}>Drop</span>
    <br>
  {{/each}}
{{/each}}
{{outlet}}
<br>
<br>

initializers.pretender.js

export function returnJSON(status, body) {
  return json(...arguments);
};

export function json(status, body) {
  if (arguments.length === 1) {
    body = status;
    status = 200;
  }
  
  return function() {
  	return [
  		status,
  	  { "Content-Type": "application/json" },
  	  JSON.stringify(body)
  	];
  };
};

export const server = new Pretender();

export function initialize() {
  server.handledRequest = function(verb, path, request) {
    console.log(`handled request to ${verb} ${path}`);
  }

  server.unhandledRequest = function(verb, path, request) {
    console.log(`unhandled request ${verb} ${path}`);
  }

  server.map(function() {
    this.post('/providers', returnJSON({
      data: []
    }));
    this.post('/features', returnJSON({
      data: []
    }));
    this.delete('/features', returnJSON({
      data: []
    }));
  });
};

export default {
  name: 'pretender',
  initialize
};

models.feature.js

import DS from 'ember-data';

const {
  attr,
  belongsTo
} = DS;

export default DS.Model.extend({
  name: attr('string'),
  provider: belongsTo('provider', { async: true })
});

models.provider.js

import DS from 'ember-data';

const {
  attr,
  hasMany
} = DS;

export default DS.Model.extend({
  name: attr('string'),
  features: hasMany('feature', { async: true })
});

routes.application.js

import Ember from 'ember';
import { server, json } from '../initializers/pretender';

export default Ember.Route.extend({
  model() {
    this.store
      .createRecord('provider', {name: 'Provider'})
    	.save()
    	.then((provider) => {
      	this.store
      		.createRecord('feature', {
            name: 'Feature 1',
            provider: provider
          })
    			.save();
    
				this.store
      		.createRecord('feature', {
            name: 'Feature 2',
            provider: provider
          })
    			.save();
      });
    this.store.createRecord('provider', {name: 'Best Provider'});
    return this.store.findAll('provider');
  }
});

twiddle.json

{
  "version": "0.5.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.2.0",
    "ember-data": "2.2.1",
    "ember-template-compiler": "2.2.0",
    "route-recognizer": "https://rawgit.com/tildeio/route-recognizer/56f5fcec6ae58d8e86b5dc77609809fb91198142/dist/route-recognizer.js",
    "FakeXMLHttpRequest": "https://rawgit.com/pretenderjs/FakeXMLHttpRequest/23c3a96b5b24f1bfe595867437e4f128a29c2840/fake_xml_http_request.js",
    "pretender": "https://rawgit.com/pretenderjs/pretender/c6de9afe18b1472aded2592f5a80ad9a26a0e262/pretender.js"
  }
}