anchor.diff:  # start the virtual framebuffer
   RUN /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -ac -screen 0 1280x1024x16
   
  +# set the app SHA
  +ENV APP_SHA 823d4d5806ed59ed82a041c5f5def45b6b16dafe
  +
   # run up testbot
   RUN mkdir -p /srv/testbot
  +RUN chown testbot:testbot /srv/testbot
   WORKDIR /srv/testbot
  +
  +# run as testbot
  +USER testbot
   RUN wget https://github.com/rtc-io/rtc-testbot/archive/$APP_SHA.tar.gz -O app.tar.gz
   RUN tar xf app.tar.gz --strip-components=1
   RUN rm app.tar.gz
  
positive.code: # TODO: configure video loopback
  # RUN /tmp/setup-loopbackvideo.sh
  
  # create the testbot user
  RUN useradd -p testbot testbot
  RUN mkdir -p /home/testbot
  RUN chown testbot /home/testbot
  
  # install chrome
  RUN wget https://dl.google.com/linux/direct/$CHROME_DEB
  RUN dpkg --install --force-overwrite --force-confdef $CHROME_DEB || sudo apt-get -y -f install
  
negative.code: MAINTAINER Damon Oehlman <damon.oehlman@nicta.com.au>
  
  # configure environment
  ENV DISPLAY :99.0
  ENV CHROME_DEB google-chrome-stable_current_amd64.deb
  ENV HOME /home/testbot
  
  # configure ports that will be exposed
  EXPOSE 3000:80
  
  # use aarnet mirror for quicker building while developing
  RUN sed -i 's/archive.ubuntu.com/mirror.aarnet.edu.au\/pub\/ubuntu\/archive/g' /etc/apt/sources.list
  
  # create the testbot user
  RUN mkdir -p /home/testbot
  RUN useradd --password testbot --home /home/testbot testbot
  RUN chown testbot:testbot /home/testbot
  WORKDIR /home/testbot
  
  # install wget and curl
  RUN apt-get -y update
  