Merge branch 'stale-read-delete-admin' into 'master'

Prevent removing all admins of a group using the default DB

Closes #644

See merge request !1207

arkindex/users/api.py

@@ -641,11 +641,11 @@ class MembershipDetails(RetrieveUpdateDestroyAPIView):
             )
 
     def perform_destroy(self, instance):
-        # At list one admin member must exist except for workers which depends on their repositories
+        # At least one admin member must exist except for workers which depends on their repositories
         if (
             instance.content_type != ContentType.objects.get_for_model(Worker)
             and instance.level >= Role.Admin.value
-            and instance.content_object.memberships.filter(level__gte=Role.Admin.value).count() < 2
+            and instance.content_object.memberships.using('default').filter(level__gte=Role.Admin.value).count() < 2
         ):
             raise ValidationError({'detail': ['Removing all memberships with an admin privilege is not possible.']})
         return super().perform_destroy(instance)