I read through #1350 but I'm still a bit confused. I'd expect the following to work (dokku 4.1):

1. Have a Dockerfile deployment that works.
2. Add a Procfile that defines different commands for a web and a worker process type.
3. Deploy and have the web process scale to 1 using the command from the Procfile.
4. Scale the worker type to 1 using ps:scale and have another instance of the docker image started running the worker command from the Procfile.

Is this a thing that's possible? I'm unclear on why It'd be required to do this in the app/image itself since buildpack-based deploys do this exactly and are also docker images. If you do think it's possible w/o breaking some kind of other feature compatibility then I'm happy to work on it.