anchor.diff:  
   WORKDIR /home/nugrid
   
  -#test script
  -#RUN sh /srv/singleuser/singleuser.sh -h
  -CMD ["sh", "/srv/singleuser/singleuser.sh"]
  +CMD /bin/bash /srv/singleuser/singleuser.sh
  
positive.code: 
  RUN useradd -d /home/nugrid -m -c "" nugrid && \
      chown -R nugrid:nugrid /home/nugrid && \
      chmod 755 /usr/local/bin/jupyterhub-singleuser
  #    chmod 755 /usr/local/bin/jupyterhub-singleuser && \
  #    chmod 755 /srv/singleuser/singleuser.sh
  
  USER nugrid
  
  
negative.code: 
  EXPOSE 8888
  
  RUN apt-get update && apt-get --no-install-recommends install --yes \
      python2.7 python3 python3-pip git\
      npm nodejs-legacy && \
      npm install -g configurable-http-proxy && \
      apt-get autoremove --yes && apt-get clean all && \
      rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
  
  RUN pip3 install --upgrade pip && \
      pip3 install setuptools && \
      pip3 install ipython && \
      pip3 install git+git://github.com/jupyterhub/jupyterhub@267994b191fc72fbbaec00b1ad41627e6539fdae && \
      pip3 install notebook
  #   install jupyterhub at commit 267994b191fc72fbbaec00b1ad41627e6539fdae because master is unstable and 0.6.1 is too old
  
  COPY jupyterhub-singleuser /usr/local/bin/jupyterhub-singleuser
  
  