如何升级设计2.1.2来设计3.2.2

I want to upgrade my current devise from 2.1.2 to 3.2.2 I added the secret_key to the initialiser so the rails server starts fine. But when I try to login I can't. Examining the logs didn't make me any smarter. I just get a 401 Unauthorized exception in the Rails log.I want to upgrade my current devise from 2.1.2