content: ########## How To Use Docker Image ###############
  ##
  ##  Install docker utility
  ##  Download docker image: docker pull denny/gitlab:v1
  ##
  ##  Start container:
  ##   docker run -t -d --privileged --name my-gitlab -h gitlab -p 40053:40053 -p 61422:22 -p 61480:80 denny/gitlab:v1 /usr/sbin/sshd -D
  ##
  ##   docker exec -it my-gitlab bash
  ##     sysctl -w kernel.shmmax=17179869184
  ##     ps -ef | grep runsvdir-start
  ##     nohup /opt/gitlab/embedded/bin/runsvdir-start &
  ##     gitlab-ctl stop
  ##     mv /var/opt/gitlab/gitlab-rails/sockets/gitlab.socket /tmp/
  ##
  ##     sed -i "s/external_url 'http:\/\/.*'/external_url 'http:\/\/git.test.com'/g" /etc/gitlab/gitlab.rb
  ##     head /etc/gitlab/gitlab.rb
  ##
  ##     gitlab-ctl start
  ##     gitlab-ctl status
  ##     # reset db, note this step is dangerous: /opt/gitlab/bin/gitlab-rake db:schema:load db:seed_fu
  ##     gitlab-ctl reconfigure
  ##     gitlab-ctl tail
  ##     curl http://127.0.0.1:80
  ##     Reset root password
  ##     Reset inject ssh key file
  ##     smtp configuration
  ##################################################
  
  FROM denny/ruby2:v1
  MAINTAINER DennyZhang.com <http://dennyzhang.com>
  
  ########################################################################################
  # https://about.gitlab.com/downloads/#ubuntu1404
  apt-get install vim lsof
  apt-get install curl openssh-server ca-certificates postfix
  curl https://packages.gitlab.com/install/repositories/gitlab/gitlab-ce/script.deb.sh | sudo bash
  apt-get install gitlab-ce
  gitlab-ctl reconfigure
  
  # Browse in GUI: Username/Password: root/5iveL!fe (it might has been changed)
  
  # TODO: configure smtp email sending
  
  # clean up
  rm -rf /var/cache/*
  rm -rf /tmp/* /var/tmp/*
  rm -rf /usr/share/doc && \
  apt-get clean && apt-get autoclean
  ########################################################################################
  