add TODO

Author: lobsterkatie

Diff for: src/sentry/models/organization.py

@@ -320,6 +320,7 @@ def get_owners(self) -> Sequence[RpcUser]:
 
     def get_default_owner(self) -> RpcUser:
         if not hasattr(self, "_default_owner"):
+            # TODO: Investigate how an org can have no owners
             self._default_owner = self.get_owners()[0]
         return self._default_owner