#29 - class members page

https://trello.com/c/OmABUd3l/29-as-an-instructor-i-want-to-see-on-the-student-roster-page-which-students-have-not-yet-accepted-the-invite-so-i-can-resend-them-a

This is the first version, it probably needs more work on the UI side so let me know what needs to be changed.