For docker, you need to change the http hostname in the server manager config.yml to use 0.0.0.0 instead of localhost. this will make it available for docker to bind to the host machine. Hope this helps
m( And the info is right there in the config's comment. Sorry again. Maybe a hint in the README on GitHub prevents further "does not work mimimi" ;-)
Aaaand it's working, lads & gents. Looking forward to check this out.