Just curious, why do you need gunicorn for auto-restarting the server inside a docker container, if you can just restart the container? It's pretty lightweight operation for config changes, imo.
Yes, you can restart the container too but it will not be real-time and sometimes when you restart docker daemon might take longer and you might have to wait to check your update.
Restarting the container is manual work. I prefer restarts being automatically taken care by watch tools or the server.
Another solution could be using docker in swarm mode to let docker automatically restart containers