Graduate Committee Activity Schema and Tests

Implements the schema and tests for the Graduate Committee Activity Schema. The number of committees and number of each role are not stored in the schema; I intend for these to be dynamically generated when needed by querying the collection for the schema. 

Both 'grunt' and 'grunt test' compile and run successfully, and all related tests pass.

I will leave this request open for a couple of hours before merging to allow others to review it. You are free to merge it before hand if you feel it is satisfactory.