Restricts views based on current logged in user - related to #6. Also adds a Team view.

Will wait until this is pushed to Openshift and verified as working to
close this issue.
Adding group property to course roster serialization
Adding assignments to lesson serialization
Adding database fixtures to simplify database rebuilds
Adding assignment submission serializer
fixed results returning with duplicate values due to django joins
Merge pull request #3 from dhm116/filter_views_by_current_user

Filter views by current user