add Dockerfile

Dockerfile

+FROM python:3.9-slim
+
+LABEL maintainer="Matteo Spanio"
+
+WORKDIR /app
+
+COPY packager.py requirements.txt config.yaml ./
+
+RUN pip install -r requirements.txt
+
+VOLUME [ "/data" ]
+
+CMD [ "python3", "packager.py", "-h" ]