provide doc on how to use in production

[aae42]

not sure if i know, but i'm thinking of like a systemd service for ubuntu:

set up a propel user and/or group to run as (this way you can grant things access to those) and run the server in the background

provide a config in /etc/propel/propel_config.yaml (maybe put this in a list of locations that viper can check?)

add an option to dump logs to a specific location (like /var/log/propel/propel_log.ndjson in the case of the service setup)