I want to lazy load those post comments without embedding comment ids in my post GET JSON

ember-data-lazy-loading.js

// My models:
App.Post = DS.Model.extend({
  content: DS.attr('string'),
  comments: DS.hasMany('App.Comment')
});

App.Comment = DS.Model.extend({
  content: DS.attr('string'),
  post: DS.belongsTo('App.Post')
});

// My GET request JSON does look like the following:
{
  "post": {
    "content": "Some content"
  }
}
// whereas ember-data is looking for something like this:
{
  "post": {
    "content": "Some content"
    "comments": [1, 2, 3] // embedded comments ids
  }
}

// How can I do something as the following somewhere in an ObjectController without using a findQuery:
this.get('content.comments') // do something whit those comments

// ... I tried the following trick:
App.Post = DS.Model.extend({
  content: DS.attr('string'),
  comments: function() {
    return App.Comment.find({postId: this.get('id')});
  }.property('id')
});

App.Comment = DS.Model.extend({
  content: DS.attr('string'),
  postId: DS.attr('number')
});

this.get('content.comments') // this line seems to work as expected

// But if I add a new comment associated to that post somewhere in a controller:
App.Post.createRecord({
  postId: this.get('content.id')
})

// my post comments property isnt updated nor the findQuery cause findQuery returns AdapterPopulatedRecordArray

// What we want is a RecordArray that remains up to date even when we add new records to this post.
// Let's try with filter method instead of findQuery though:
App.Post = DS.Model.extend({
  content: DS.attr('string'),
  comments: function() {
    postId = this.get('id');
    return App.Comment.filter({post_id: postId}, function(data) {
      return data.get('postId') == postId;
    });
  }.property('id')
});

this.get('content.comments') // this line seems to keep working as expected
App.Post.createRecord({
  postId: this.get('content.id')
})

// And booom, we added a new record and our array almost immediatly contains it!