Send gunicorn access log to stdout

Because:
- We want to be able to see wth is going on

Dockerfile

@@ -7,4 +7,4 @@ RUN mkdir /app
 COPY settings.py /app/
 ENV MIST_ARGUS_SETTINGS /app/settings.py
 
-CMD ["gunicorn", "--log-level=debug", "--bind", "0.0.0.0:8000", "mist_argus.webhook:app"]
+CMD ["gunicorn", "--log-level=debug", "--access-logfile", "-", "--bind", "0.0.0.0:8000", "mist_argus.webhook:app"]