Don't Merge Me...except non-existent changes

[CarsonDavis]

Don't actually merge this pr. It looks like api_app/models.py set_change_updated_at was blocking database load when it hits a bad change link.

If you want to load the database on local,

• check out this branch
• delete pre-existing docker volumes and containers
• rebuild the docker
• enter the webapp container and python manage.py loaddata

Here is the link to the prod backup

I'm a bit worried that we have badly linked change objects in prod that are causing this. It would be worth doing an investigation of the change objects to see what's going on.