Yeah, installing mysql locally is fine, but might make it a little confusing since you now have two separate mysql instances running, but this should clarify.

To connect from the droplet itself, we need to look to the docker networking to find the IP the mysql container is running at by running this command:

docker inspect --format "{{ .NetworkSettings.IPAddress }}" steem_mysql

For example, I get 172.17.0.2 as the IP. Then, you can connect using the IP returned from that command:

mysql -h 172.17.0.2 -u root -p

If you are connecting from any remote system, you can just use the public IP of this droplet with the normal port 3306.