While I personally like the foreman-installer, it’s unsuited to a proper container deployment. It’s aimed at installing a whole stack where a real container deployment ideally splits it into one process per container. Running a whole stack inside a container with a process manager is IMHO a VM so I’d recommend using a VM in that case.
As pointed out in Docker image for running The Foreman the more likely path forward with containers is deploying to openshift which we have a proof of concept for now.
tl;dr: IMHO we have no supported way of running foreman in containers, but it’s on the roadmap. If you’d like to help make it happen, we’d appreciate any help.