Sure, try doing the following:-
type in docker ps
When I do this I get a couple of lines returned. Look for the line that says the port 5432 and take a note of the container id, mine says 598d32af7efd.
type in docker inspect 598d32af7efd |pg or whatever your container id is.
You will see from the output something that says NetworkSettings, look for the line that says IPAddress. Make a note of the IPAddress, mine says 172.17.0.2
Now enter psql -h 172.17.0.2 -U musicbrainz or whatever your IPAddress is.
You will then be prompted to enter your password.
Hope this helps, if you have any problems then ping me.