I recently set up Dokku. It has a few gotchas. I happen to hit it right when 0.3.13 came out, which broke integration with supervisord (and all other process managers). A few days later it was fixed. There are quite a few places where I had to use fairly advanced UNIX-fu to debug it, that was not covered by any dokku or related docs. Having said that, I really like it. Once you get it up and running, it works well, and I am happy to pay $10/month to host multiple side projects on one DO instance rather than paying for Heroku (yes, I'd need to pay with how these projects operate).