IMHO Dokku still outperforms all other open-source alternatives for deploying Rails apps. There are a few proprietary alternatives that still manage the job with far more simplicity, but those are paid... I have tried to deploy with Kamal, DHHs Junta preferred way, but is still not better than Dokku in it's management and simplicity, and top of that, if follows the framework's latest trend of poor-to-no documentation.