Document Docker daemon mode

[marcelstoer]

I suspect that most people would rather want to run the TTN container in daemon mode rather than interactive mode (-dt vs. -it). It would run in the background and not block the CLI but you won't see the log output that normally spills to the console.

docker logs <container-id> could make that visible again if necessary. Or docker attach <container-id>. Or docker exec -i <container-id> /bin/bash and then poke around the container.