Resolve "MultipleObjectsReturned at /app/alsijil/me/ - get() returned more than one Group -- it returned 18!"

Closes #182 (closed)

aleksis/apps/alsijil/forms.py

@@ -256,11 +256,13 @@ class AssignGroupRoleForm(forms.ModelForm):
                 )
             else:
                 persons = persons.filter(member_of__owners=self.request.user.person)
-            self.fields["person"].queryset = persons
+            self.fields["person"].queryset = persons.distinct()
 
             if "groups" not in initial:
-                groups = Group.objects.for_current_school_term_or_all().filter(
-                    owners=self.request.user.person
+                groups = (
+                    Group.objects.for_current_school_term_or_all()
+                    .filter(owners=self.request.user.person)
+                    .distinct()
                 )
                 self.fields["groups"].queryset = groups
 
@@ -332,7 +334,7 @@ class FilterRegisterObjectForm(forms.Form):
                 | Q(lessons__lesson_periods__substitutions__teachers=person)
                 | Q(events__teachers=person)
                 | Q(extra_lessons__teachers=person)
-            )
+            ).distinct()
         elif not for_person:
             groups = Group.objects.all()
         self.fields["group"].queryset = groups