Dockerfile configuration

I need to run a docker container, that runs a program. I want to be able to re-read the configuration INSIDE that container, (like kill -HUP <pid>) however when that container is a single process, docker will just terminate the whole container once any kill signal is sent to the process. The solution is to run the main process as BASH or something, and the other processes underneath it, so if a process is killed or restarted, it doesnt kill the whole container.

https://ahmet.im/blog/minimal-init-process-for-containers/. -- this is a blog showing a bunch of methods how to do it.

I just need a Docker configuration file that would make that happen.