anchor.diff:  # Instructions for using this Dockerfile to create a cyber-dojo
   # server inside a docker container.
   #
  -# Setup the katas/ folder on the host
  -# -----------------------------------
  +# 1. Setup the katas/ folder on the host
  +# --------------------------------------
   # $ sudo mkdir -p /var/www/cyber-dojo/katas/
   # $ sudo chmod g+s /var/www/cyber-dojo/katas/
   # $ sudo chown -R 33:33 /var/www/cyber-dojo/katas/
   #
  -# Pull the language images you want
  -# ---------------------------------
  +# 2. Pull the language+test images you want
  +# -----------------------------------------
   # $ docker pull cyberdojofoundation/gcc_assert
   # $ docker pull ...
   #
  -# Build the image from this Dockerfile
  -# ------------------------------------
  +# 3. Build the image from this Dockerfile
  +# ---------------------------------------
   # $ docker build -t cyberdojofoundation/server:1.0 .
   #
  -# Run the image
  -# -------------
  +# 4. Run the image
  +# ----------------
   # This needs a data-container for katas/
   # See docker_images_katas folder.
   #
  
positive.code: RUN cp /etc/apache2/sites-available/default-ssl.conf /etc/apache2/sites-available/cyber-dojo-ssl.conf
  RUN sed 's/www.html/www\/cyber-dojo\/public/' < /etc/apache2/sites-available/default-ssl.conf > /etc/apache2/sites-available/cyber-dojo-ssl.conf
  
  # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  # Install cyber-dojo
  
  
negative.code: #              --name=cyber-dojo \
  #              -p 80:80 -p 443:443 cyberdojofoundation/server:1.0
  #
  # 6. Refresh the caches inside the container
  # ------------------------------------------
  # This will make the images pulled in step 2 visible.
  # $ docker exec cyber-dojo bash -c /var/www/cyber-dojo/caches/refresh_all.sh
  #
  # 7. Find it's IP address on MacOSX Docker-Quickstart-Terminal
  # ------------------------------------------------------------
  # $ docker-machine ip default
  
  
  RUN apt-get update && apt-get install --no-install-recommends -y \
          apache2 curl git build-essential zlibc zlib1g-dev \
  