Can't login with username root and password webmin

[zhouchunyu]

Thanks for building this image.
What's the default login username and password?
Here is how I start this image.
I am using macbook and I map localhost port 80 to container port 10000 like this

docker run -it -p 80:10000 -v /Users/zhouchunyu/workspace/docker/webmin:/var/run/container-control tragus/webmin

Also I can't going to the container bash to change the password using

docker run -it -p 80:10000 -v /Users/zhouchunyu/workspace/docker/webmin:/var/run/container-control tragus/webmin /bin/bash