How would I fix this one-to-many polymorphic relationship in ember-data?

There are four models:

• Idea and Comment, which extend Thought


• Vote

Both an idea and a comment can have multiple votes. However, each vote can only relate to one idea/comment.

Note: Idea is analogous with Post for this example.

The solution I came up with is in this jsbin: http://ift.tt/1ySLyuM

The above code dies when I try to fetch the vote records. It works fine while getting the ideas. Considering how simple this example is, I'm sure I don't understand polymorphic relationships as well as I think I do. Anyways, any hints as to what I'm missing or doing wrong?