Love this guide. Ran it on my home server without a hitch. Unfortunately, on my VPS, I get the following. Will probably just change VPS.

Loading image from someguy123/steem
Using default tag: latest
Warning: failed to get default registry endpoint from daemon (Cannot connect to the Dock
er daemon at unix:///var/run/docker.sock. Is the docker daemon running?). Using system d
efault: https://index.docker.io/v1/
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon
running?
Tagging as steem
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon
running?
Installation completed. You may now configure or run the server

Feel free to hit me up @someguy123 if you want to look at the VPS image. Not expecting a fix, but you might be interested for bug fixing purposes.