message: Reduce docker image size by +50%
diff: -FROM python:3.6.8
  +FROM python:3.6.8-slim
  -WORKDIR /opt/ml/project
  +WORKDIR /opt/app
  # Create output directory as its expected
  RUN mkdir output
  +# Upgrade pip and setuptools
  +RUN pip install -U pip==19.2.3 setuptools==41.2.0
  +
  # First copy scripts and setup.py to install dependencies
  # and avoid reinstalling dependencies when only changing the code
  COPY setup.py setup.py
  -# Mostly taken from setup.py but split into
  -# required, dev and cpu to trigger image layer
  -# updates less often
  -RUN pip install -U pip==19.2.3
  -RUN pip install -U setuptools==41.2.0
  -
  -# Now install required_installs as well as dev and cpu
  -RUN pip install -e .[cpu,dev]
  +# Install only install_requires
  +RUN python setup.py egg_info && \
  + LN=$(awk '/tensorflow/{ print NR; exit }' xain.egg-info/requires.txt) && \
  + IR=$(head -n $LN xain.egg-info/requires.txt | awk '{gsub(/\[.+\]/,"");}1') && \
  + pip install $IR
  -COPY scripts scripts
  COPY xain xain
  -# Rerun to install scripts
  -RUN ./scripts/setup.sh
  +RUN pip install -e .
  