anchor.diff:  # add remaining sources
   COPY imagetagger /app/src/imagetagger
   
  -# confiure runtime environment
  -RUN mkdir /app/data /app/static /app/config
  -RUN cp /app/src/imagetagger/imagetagger/settings.py.example /app/config/settings.py
  -RUN ln -sf /app/config/settings.py /app/src/imagetagger/imagetagger/settings.py
  +# configure /app/config/imagetagger_settings to be python importable so that one can use their own settings file
  +RUN mkdir -p /app/data /app/static /app/config/imagetagger_settings
  +RUN touch /app/config/imagetagger_settings/__init__.py
  +ENV PYTHONPATH=$PYTHONPATH:/app/config:/app/src/imagetagger
  +
  +# configure runtime environment
   RUN sed -i 's/env python/env python3/g' /app/src/imagetagger/manage.py
   
   ARG UID_WWW_DATA=5008
  
positive.code: RUN ln -sf /app/bin/* /usr/local/bin
  ENTRYPOINT ["/usr/local/bin/run"]
  ENV IN_DOCKER=true
  
  # add image metadata
  EXPOSE 3008
  
negative.code: 
  # add requirements file
  WORKDIR /app/src
  COPY imagetagger/requirements.txt /app/src/requirements.txt
  
  # install python dependencies
  RUN pip3 install -r /app/src/requirements.txt
  