add coveralls
add grade model, rough grade views
fix grade views, add grade edit
create some new methods in grades controller
add test for new grade - works when run on file, not when run on directory WTF
Do not change days_of_week to string before save.

* Remove empty values before save but retain the array storage.
* Provide convenience method for showing as a string.
* Replace all calls with string call.
add populate task for sample data