@scottslowe So I went the ugly way and created a shell script called na--cli.sh containing:
#!/bin/bash
/usr/local/bundle/bin/na "$@"
Then I used an add command to the Dockerfile (and a chmod +x)
Then set the entrypoint to
ENTRYPOINT ["/usr/local/bin/na-cli.sh"]
With that, I can call the process and pass parameters like --version but it doesn't seem to fully work. It doesn't help that I don't know that tool, I guess, I get some "No database found"