edx/edx-ora2 — pull request #336 by wedaly (2014-05-16 12:52:33+00:00)
Title: Uniqueness constraints for student training

* Add uniqueness constraints for `StudentTrainingWorkflow` and `StudentTrainingWorkflowItem`
* Gracefully handle `IntegrityError`s
* Move test constants into a shared module.

@stephensanchez