Deploying Rails 6 application with Dokku

Heroku, AWS, Google Cloud are great services for hosting Rails application but they are expensive. If you are developing a small app, kicking off a startup or just playing with Rails you can use cheaper solutions - cloud hosting, like DigitalOcean or Upcloud. The problem is the setup - you need to install dependencies on your own. Then deploy your application manually or using for example capistrano, which also requirers a lot of setup. What if we had self-hosted heroku?.