Remove the pip cache in the docker image to reduce the size

.dockerignore

@@ -0,0 +1,3 @@
+**/__pycache__
+**/.pytest_cache/
+.git

Dockerfile

@@ -2,20 +2,22 @@ FROM python:3.7-slim-stretch
 
 RUN apt-get update && \
 apt-get upgrade -y && \
-apt-get -y install gcc git libspatialindex-dev curl &&  \
+apt-get -y install gcc git libspatialindex-dev curl coinor-cbc &&  \
 rm -rf /var/lib/apt/lists/*
 
 RUN curl -sL https://deb.nodesource.com/setup_17.x | bash -
-RUN apt-get -y install nodejs && node --version && npm --version
+RUN apt-get -y install nodejs && node --version && npm --version &&  \
+rm -rf /var/lib/apt/lists/*
 
-RUN apt-get install -y coinor-cbc
+#RUN apt-get install -y coinor-cbc &&  \
+#rm -rf /var/lib/apt/lists/*
 
-RUN /usr/local/bin/python -m pip install --upgrade pip
+RUN /usr/local/bin/python -m pip install --no-cache-dir --compile --upgrade pip
 
 COPY ./scripts .
 COPY . .
 
-RUN pip3 install -e .
+RUN pip3 install --no-cache-dir --compile -e . && pip cache purge
 ENV PYTHONPATH=./scripts:${PYTHONPATH}
 
 ENTRYPOINT ["python3"]