Update Documentation Around Services and Custom Networks (Docker Runner)
Description
If a user of a docker runner adds said runner to a custom network via the docker-network-mode parameter there should be a warning / documentation that services will not be health checked properly due to the fact that the container will not be linked properly to the health checker (which is by design in Docker). This is confusing until you read the Docker documentation on links.
Proposal
Just document that using a custom network in conjunction with services are not supported at this time. It'd be cool if linking containers worked with custom networks though, I feel it might be possible simply by having a more complex health checker script / using something besides the legacy link option in docker.
Links to related issues and merge requests / references
I originally filed this as a bug, before digging into the docker: