What problem are you trying to solve with Submitty
Most students are registered in the course for a grade.
But we also have a small number of students who might be auditing the course (ungraded).
Or students who are still on the registration but have been given the status of withdrawn or late drop (again ungraded).

Describe the way you'd like to solve this problem

1. Let's add another column to the users table of the database to handle this.

   field name = 'registration_type'
   type = character varying(255)
   default value = 'graded'
   other values 'audit' or 'withdrawn' or ... could add other things eventually
   hmm... this might be convenient to use for teaching staff who are not officially registered but are testing

2. let's display this value in the manage students/graders -> edit student/graders panel
   and allow editing of the value on that panel
   and make sure we can upload files to initialize this data in bulk

3. It should also be exported through rainbow grades. Rainbow grades can then use this information for display and statistics.

4. TA grading statistics might also want to use this information.

Describe any potential alternatives you'd tried to solve the problem

Alternately we could have an enum instead of a string. But that would be less convenient to expand functionality.