Add user to group

If you see:

Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get "http://%2Fvar%2Frun%2Fdocker.sock/v1.40/containers/json": dial unix /var/run/docker.sock: connect: permission denied

Your user probably isn’t in the Docker group. Fix like so:

sudo gpasswd -a $USER docker

Log out, and try again.