CYB-217 - Enable detailed view & allow videos to be played

https://jira.ets.berkeley.edu/jira/browse/CYB-217
If you want to remove .author field from Comment, what about MediaURL and Attachment?  They all have the canvas_user_id.   This would simplify a lot of code on the back end, and also keep things more consistent -- there would be no need for database changes outside the Student table if the name changes.    A call to the students controller with a #index action could return a list of students and their names (not yet implemented)

This is just a suggestion; the API for those models passes on the name, but updating other tables when the name changes has not been implemented.  But there's a 'gotchya' in that if a user hasn't had a student record created yet, the values returned from the users call might not have an entry -- but I'd have to think that through, the interaction of request cycles etc.