It’s not ready yet. It bothers us too but we preferred to release early ORM 5 and catch up on tooling later. Small team, yadayadayada. Let us know if that’s an itch you want to scratch and want to contribute.
Things are not that bad though. You can still use Hibernate Tools with Hibernate ORM 4 libraries to generate the mappings/schemas that will work with Hibernate ORM 5.
You can check out our old FAQs, but they are mostly out of date.