Promote: remove promoting groups by team-members for keeps
If a course-team doesn't want to be promoted by a certain group. They should be able to remove that group for keeps.
So I guess, we should store removed groups in the course.
Plus we need to add a "are you sure to remove that group from your course? It will be removed from all events and they will not be able to promote your course again"
and have an option to undo this change by course-team-members by showing removed groups to them and option to re-enable them.
Edited by 1u