Currently I get the console error "Your server returned a hash with the key messages but you have no mapping for it". Ember expects to get the newly created object back from the POST request. Even if you just spit back exactly what was sent, that will at least suppress the console error. See $controllers->post('/course_summaries') for an example. 

Sorry, I know that the REST file is inconsistent and some places return 'messages' => 'success' on creating, but that's older code.