Select related users when displaying history in admin (#496)

* Select related users

This is to avoid n+1 queries

* make format

Author: rudkjobing

simple_history/admin.py

@@ -48,7 +48,9 @@ def history_view(self, request, object_id, extra_context=None):
         pk_name = opts.pk.attname
         history = getattr(model, model._meta.simple_history_manager_attribute)
         object_id = unquote(object_id)
-        action_list = history.filter(**{pk_name: object_id})
+        action_list = history.filter(**{pk_name: object_id}).select_related(
+            "history_user"
+        )
         history_list_display = getattr(self, "history_list_display", [])
         # If no history was found, see whether this object even exists.
         try: