Request - Support exec/entrypoint for exited services.

[chriseaton]

This project works great for starting up a a service on a schedule, but I noticed that if I specify an exec command - it expects the container to still be running. That's fine - in fact a great feature, but it might be nice if the the service container had exited it spins it back up to run the exec - or alternatively have a way to override the entrypoint of a service on schedule.