[wip] remove index_together support

Author: timgraham

django_mongodb/schema.py

@@ -42,9 +42,6 @@ def _create_model_indexes(self, model):
                 self._add_field_index(model, field)
             elif self._field_should_have_unique(field):
                 self._add_field_unique(model, field)
-        # Meta.index_together (RemovedInDjango51Warning)
-        for field_names in model._meta.index_together:
-            self._add_composed_index(model, field_names)
         # Meta.unique_together
         if model._meta.unique_together:
             self.alter_unique_together(model, [], model._meta.unique_together)