Protect learner group related entities from double add
Protect learner group related entities from double add

Users, children, and instructor groups relationships needed the
protection we use on all many to many relationships.

justinchu17/ilios,dartajax/ilios,thecoolestguy/ilios,stopfstedt/ilios,Trott/ilios,justinchu17/ilios,thecoolestguy/ilios,Trott/ilios,justinchu17/ilios,justinchu17/ilios,stopfstedt/ilios,ilios/ilios,dartajax/ilios,ilios/ilios