Mirage - embedded relationship

mirage.config.js

export default function() {
  //window.server = this;
  
  this.get('/foo', (schema, request) => {
    return schema.users.find(1);
  });
};

mirage.models.post.js

import { Model, belongsTo } from 'ember-cli-mirage';

export default Model.extend({
  
  user: belongsTo()

});

mirage.models.user.js

import { Model, hasMany } from 'ember-cli-mirage';

export default Model.extend({
  
  posts: hasMany()

});

mirage.scenarios.default.js

export default function(server) {
  server.create('user', {
    posts: server.createList('post', 3)
  });
}

mirage.serializers.application.js

import { RestSerializer } from 'ember-cli-mirage';

export default RestSerializer.extend({
  alwaysIncludeLinkageData: true
})

mirage.serializers.user.js

import ApplicationSerializer from './application';

export default ApplicationSerializer.extend({
  embed: true,
  include: ['posts']
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  
  model() {
    return Ember.$.getJSON('/foo');
  },

  setupController(controller, model) {
    controller.set('json', JSON.stringify(model, null, 2));
  }
  
  
});

templates.application.hbs

<div class='pa4'>
  <h1>Mirage boilerplate</h1>

  <pre>
{{json}}
  </pre>
</div>

twiddle.json

{
  "version": "0.15.0",
  "ENV": {
    "ember-cli-mirage": {
      "enabled": true
    }
  },
  "EmberENV": {
  },
  "options": {
    "use_pods": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  }, 
  "addons": {
    "ember-cli-mirage": "0.4.9"
  }
}