One-way relationships with ember-data

I am trying to set up a simple platform for employees to give feedback to each other. I am using ember-data (from beta branch).

Models:

App.Employee = DS.Model.extend({
    name: DS.attr()
})

App.Feedback = DS.Model.extend({
    text: DS.attr(),
    employee: DS.belongsTo('employee', {async: true})
})

Router (simplyfied):

App.Router.map(function(){
    this.resource('profile', {path: 'profile/profile_id'})
})

App.ProfileRoute = Ember.Route.extend({
     model: function(params){
        return this.store.find('employee', params.profile_id);
     }
})

Data:

App.Employee.reopenClass({
  FIXTURES: [
    { id: 1, name: 'Trek'},
    { id: 2, name: 'Tom'}
  ]
});

App.Feedback.reopenClass({
  FIXTURES: [
    { id: 1, text: 'Topic1', employee: 1},
    { id: 2, text: 'Topic2', employee: 2},
    { id: 3, text: 'Topic3', employee: 1},
    { id: 4, text: 'Topic4', employee: 2}
  ]
});

I can't get a list of feedbacks to display in the template profile.

Template:

{{#each feedback in model.feedback}}
    {{feedback.text}}
{{/each}}

I can't figure out, what I'm doing wrong.

Should I specify feedbacks: DS.hasMany('feedback') under App.Employee? Or should I do this through the controller?