Added database constraint on AuthRocket

[colts661]

Fixed #559. The constraint error is handled in both create_account() and update_account(), and so the tests are built upon these two methods without committing in the tests.

[colts661]

The 422 code test in test_api for create_account() directly addresses this issue but seems to have some extra legacy handling afterwards. Please let me know:

1. What's expected in this test case after the addition of db constraint;
2. Should I move all added tests to api/tests/test_api.py altogether.

Thank you!!

[cassidysymons]

@colts661 You can delete lines 898 - 911 in test_api.py. Since the new database constraint makes the condition impossible, it's no longer necessary to test what the API does if it happens.

I'll review the rest of the PR in the next couple of hours. Thanks!

[cassidysymons]

@colts661 When you have a moment, can you please rename 0135.sql to 0136.sql in your working branch? Another PR merge created a conflict. Thanks!

[cassidysymons]

@colts661 Can you please update your working branch from biocore/microsetta-private-api:master? Patch 0135.sql isn't in your working branch and is causing the build to fail when I test it on our staging server.