So, this update is one of the annoying hacks. [A *real* `save()` happens in the model `render()` method, after calls to these methods with `force_fresh=True`.](https://github.com/lmorchard/kuma/blob/3aec0518ad87427bd9b11afc57c6b77bbf45c363/apps/wiki/models.py#L923) This single-column update is meant to gradually populate the database on view, because the columns will initially be null and I didn't want to run a full-site rebuild. Maybe that's a bad idea.