bind the logs inside docker-compose.yml

[mourginakis]

Fixes an issue where the logs could not be written to the logs/ directory in the docker container. I think the file path was interpreted wrong:

gunicorn -w 1 -b 0.0.0.0:80 --access-logfile=logs/gunicorn_access.log --error-logfile=logs/gunicorn_error.log -k eventlet node_monitor.__main__:app

Error: Error: 'logs/gunicorn_error.log' isn't writable [FileNotFoundError(2, 'No such file or directory')]

Docker containers are supposed to be stateless, so we had two options:

1. Output all logs to stdout so they get picked up by docker directly.
2. Bind the /app/logs directory in the container to the logs/ directory on the machine.

I opted for (2) because it allows us to keep our separate logfiles:

• gunicorn_access.log
• gunicorn_error.log
• node_monitor.log