Ember data not getting relationships

I'm using Ember 1.13.3 and ember-data 1.13.5.

I have 2 models with a relationship:

spot:

import DS from 'ember-data';

export default DS.Model.extend({
  user: DS.belongsTo('user'),
  description: DS.attr('string'),
  created_at: DS.attr('date'),
  image_src: DS.attr('string')
});

user:

import DS from 'ember-data';

export default DS.Model.extend({
  username: DS.attr('string'),
  email: DS.attr('string'),
  avatar: DS.attr('string'),
  spots: DS.hasMany('spot')
});

now I call in all the spots and loop over them. Everything display fine of the spot model; however, when I try to retrieve the user's username spot.user.username it doesn't work. I checked the network and not even a request is being sent out to users/:user_id.

I also tried adding asyn: true:

DS.belongsTo('user', {async: true})

but this also did not work. Is there a new way to do relationships in ember 1.13? I know that the belongsTo call is being reach because it appears as a deprecation in the ember console:

In Ember Data 2.0, relationships will be asynchronous by default. You must set `user: DS.belongsTo('user', { async: false })` if you wish for a relationship remain synchronous.