Update/anchor tests

This PR is to demonstrate a failure of the unique anchor test. DO NOT MERGE THIS PR.

It fails when we try to set an empty anchor (which should be allowed since they are not required) and when we simulate creating a new rule (ie: no id exists yet).

Unique anchors should only fail when we are adding a brand new rule and trying to set an anchor on it that already exists in the db, or when we are editing an existing rule and giving it a new anchor other than it's current one, which exists in the db from some other rule (and of course, empty anchors must still be allowed and not cause a failure).

See PR #171 for the fixed unique anchor logic working with these tests merged into it and passing.