Updated for docker

Dockerfile

@@ -0,0 +1,9 @@
+FROM python:alpine
+RUN apk add --no-cache tini
+
+ADD metrics.py /metrics.py
+ADD requirements.txt /requirements.txt
+RUN pip install -r /requirements.txt
+
+ENTRYPOINT ["/sbin/tini", "--"]
+CMD ["python" , "/metrics.py"]