+ a lot of classes for pushing submissions, deserializing submissions and theoretically mark 1 submission as primary if only 1 is allowed but more than one present
! default should be to set the newest submission as primary, (easy -> timestamp), TaskSubmissions has a field for that
! Submissions for a single task however are just a list, would need to move to a special class to contain optional primary information and need backing implementation in DB (??, android does still not have one)