anchor.diff:  
   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
  +    chmod 775 /usr/local/bin/jupyterhub-singleuser && \
  +    chmod 775 /srv/singleuser/singleuser.sh
   
   USER nugrid
   
  
positive.code: 
  EXPOSE 8888
  
  RUN apt-get update && \
      apt-get --no-install-recommends install --yes \
      python3 python3-pip git \
      npm nodejs-legacy && \
      npm install -g configurable-http-proxy
  
  RUN pip3 install --upgrade pip && \
      pip3 install setuptools && \
      pip3 install ipython
  #    pip3 install ipython && \
  #    pip3 install notebook
  
  RUN pip3 install git+git://github.com/jupyterhub/jupyterhub && \
      pip3 install notebook
  #    pip3 install git+git://github.com/jupyterhub/jupyterhub@267994b191fc72fbbaec00b1ad41627e6539fdae && \
  
  COPY jupyterhub-singleuser /usr/local/bin/jupyterhub-singleuser
  
  
negative.code: 
  WORKDIR /home/nugrid
  
  CMD /bin/bash /srv/singleuser/singleuser.sh
  