Часть страницы загружается, затем становится пустой, и я получаю следующую ошибку.

TypeError: Cannot read property 'typeKey' of undefined
    at Ember.Object.extend.modelFor (http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:19:12298)
    at Ember.Object.extend.recordForId (http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:19:8860)
    at s (http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:19:1790)
    at http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:19:1524
    at http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:18:32392
    at http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:9:22231
    at Object.l.forEach (http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:9:21553)
    at Object.u.forEach (http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:9:22198)
    at Function.a.reopenClass.eachRelationship (http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:18:32368)
    at a (http://my-app.herokuapp.com/assets/manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:19:1302) manifest-docs-cbb67138a1a7e2bbc15fdbae9b24aa06.js:9n.function.n.apply.r

Вот мои модели:

# app/models/plan.js.coffee
App.Plan = DS.Model.extend
  name: DS.attr('string')
  slug: DS.attr('string')
  project: DS.belongsTo('project')
  sections: DS.hasMany('section',{async: true})

# app/models/section.js.coffee
App.Section = DS.Model.extend
  name: DS.attr('string')
  details: DS.attr('string')
  sort_order: DS.attr('number')
  plan: DS.belongsTo('plan')
  summary_of_changes: DS.attr('string')

# app/models/project.js.coffee
App.Project = DS.Model.extend
  name: DS.attr('string')

Я бегу:

DEBUG: ------------------------------- 
DEBUG: Ember      : 1.7.1+pre.c1ec09ad 
DEBUG: Ember Data : 1.0.0-beta.9 
DEBUG: Handlebars : 1.3.0 
DEBUG: jQuery     : 1.10.2 
DEBUG: ------------------------------- 

[Редактировать: Добавлен код модели проекта] [Редактировать 2: Здесь найдено соответствующее обсуждение на форумах ember:http://discuss.emberjs.com/t/ember-data-dont-want-to-load-belongsto-relationship/5703/11]