text: Title: Gunicorn instrumentation with statsd_host
  Body: I would like to configure`--statsd-host` for [Gunicorn instrumentation](https://docs.gunicorn.org/en/stable/instrumentation.html) in `tiangolo/uvicorn-gunicorn-fastapi:python3.7-alpine3.8`. So far, I have not had success e.g. with `echo "statsd_host = 'localhost:9125'" >> /gunicorn_conf.py` in `/apps/prestart.sh`. Is there a better way to try this and is is possible at all?