Add warning about anonymous volume

[cskwrd]

The Dockerfile for the image uses an anonymous volume to persist the transformed config. This presents a problem in situations where a compose file is used. Volumes are not destroyed when changes are made to the compose file. This is in turn results in stale configuration. Additionally, it is rather difficult to debug when the configuration doesn't update as expected.

[BertrandGouny]

Thanks :)

[maxswjeon]

Please add warning to docker-compose users.

docker-compose Guide

When using docker-compose, docker-compose up -d --force-recreate does not reset anonymous volume. Run docker-compose stop [service name] and docker-compose rm [service name] and then you should run docker-compose up -d.

[cskwrd]

Is something more required for this to be merged?