Merge pull request #300 from lpmi-13/improve-dockerfile-caching

Dockerfile

@@ -1,7 +1,7 @@
 FROM python:alpine
+RUN apk add --no-cache build-base libffi-dev libxml2-dev libxslt-dev
 WORKDIR /app
 COPY . /app
-RUN apk add --no-cache build-base libffi-dev libxml2-dev libxslt-dev
 RUN /usr/local/bin/python -m pip install --upgrade pip
 RUN /usr/local/bin/python --version
 RUN pip3 install --no-cache-dir .