anchor.diff:  ## First install docker on your machine
   ## Then you can build the docker image with this command (the build looks
  -## in the current file):
  +## in this file):
   # docker build -t image-punchcardjs-demo .
   ## Then run the docker container using this command:
  -# docker run -p 5001:5000 --name prosperous-punchcards image-punchcardjs-demo
  +# docker run -p 5002:80 --name prosperous-punchcards image-punchcardjs-demo
   ##
   ## Now you should be able to open a browser (on the host) and navigate to
  -## http://localhost:5001 and see the webapp being served.
  +## http://localhost:5002 and see the webapp being served.
   ##
   ## When you're done, run
   # docker stop prosperous-punchcards
  
positive.code: # docker images
  ##
  ## Removing the image goes like this:
  # docker rmi punchcardjs-image
  
  # start from Node's offical docker image, version 7.0 (https://hub.docker.com/r/library/node/)
  FROM node:7.0
  
  # open network port (at outside of the container)
  EXPOSE 5000
  
  # do the updates
  RUN apt-get update
  
  # install version management git
  RUN apt-get install -y git
  
  # get a copy of the repository
  RUN git clone https://github.com/nlesc-sherlock/punchcardjs-demo.git 
  
  # change into the directory
  WORKDIR /punchcardjs-demo
  
  # Be explicit about which commit we're using
  RUN git checkout 12dee71297710e8cf40b43ce54194b7909402387
  
  # install the dependencies listed in package.json
  RUN npm install
  
negative.code: # fill the sites/demo/ directory with the demo website's content
  RUN npm run demo
  
  # change into the demo directory
  WORKDIR /punchcardjs-demo/docs/sites/demo
  
  # define the container's task: serving the app
  CMD python3 -m http.server 80
  