Model validations

[bjmllr]

Models which can be changed by a user directly should be checked for validity before changing the database.

• Domain

Models which can be added by a scraper should be checked for validity before adding to the database.

• Location
• PhoneNumber

[bjmllr]

When a loader encounters an invalid model, should it just log the rejection and continue?

[gxespino]

I think that's acceptable behavior.