Simple Ember.js `has-many` relationship not working

I'm running into an issue of querying data against Ember data.

I have three models:

media: which multiple models inherit from image: which inherits from media note: which is a standard model.

I'm trying to get all of the notes of an image but the query I'm trying isn't working.

---

// imageModel.js
import Ember from 'ember';
import DS from 'ember-data';
import MediaModel from 'models/mediaModel';

export default MediaModel.extend({ 
    fileName: DS.attr('string'),
    fileExt: DS.attr('string'),

    url: DS.attr('string'),
});


// mediaModel.js
import DS from 'ember-data';

export default DS.Model.extend({
    notes: DS.hasMany('note', { inverse: 'noteable' }),
});


// noteModel.js
import DS from 'ember-data';
import Ember from 'ember';

export default DS.Model.extend({
    category: DS.attr('string'),
    text: DS.attr('string'),

    image: DS.belongsTo('image'),
    noteable: DS.belongsTo('media-model', { polymorphic: true }),
});

Once I have an image, I do image.get('notes.length'), but even if an image does have notes associated with it, I'm always getting back 0. Am I querying this the wrong way?

Does the fact that image belongs to media affect how I can query the hasMany of media?

Thank you