readme: use the --format command line argument to fetch the container ip address
readme: use the --format command line argument to fetch the container ip address

bboehmke/docker-gitlab-ci,adiferd/docker-gitlab-ci,outcoldman/docker-gitlab-ci,youhong316/docker-gitlab-ci,bboehmke/docker-gitlab-ci,outcoldman/docker-gitlab-ci,youhong316/docker-gitlab-ci,sameersbn/docker-gitlab-ci,adiferd/docker-gitlab-ci,sameersbn/docker-gitlab-ci