destroy student groups when user is destroyed.
destroy student groups when user is destroyed.

edurange/edurange,donkey-hotei/edurange,edurange/edurange-server,donkey-hotei/edurange,edurange/edurange,edurange/edurange-server,edurange/edurange,donkey-hotei/edurange,edurange/edurange-server,edurange/edurange,donkey-hotei/edurange,edurange/edurange-server