I followed and modified the instructions here. This was much easier than trying to make do with the readme.
The key insight here is that you need to leave something running in the foreground.
How do I keep Docker containers running in the background? If you would like to keep your container running in detached mode, you need to run something in the foreground. An easy way to do this is to tail the /dev/null device as the CMD or ENTRYPOINT command of your Docker image. This command could also run as the last step in a custom script used with CMD or ENTRYPOINT .