Add integration tests for record listing with pretender

drf is for django rest framework. I'm not exactly sure if this is correct; I'm just following format from the docs and the active model adapter.

http://emberjs.com/guides/models/customizing-adapters/#toc_authoring-adapters
https://github.com/emberjs/data/blob/master/packages/activemodel-adapter/lib/system/active_model_adapter.js#L104

I guess '-django-rest' or '-django' could also work. Or does it need to be 'DS/djangoREST' for some reason?