docker linking - benclifford/text GitHub Wiki
launch app container with --link=production-db:db or --link=test-db-1:db
allows use of "db" hostname in config files, with docker command attaching you to correct container.
but can't destroy/rebuild production-db container - it's now a different container so app container is no longer linked to it.
requires nested container lifetimes. which is manageable but a bit awkward?
reconfiguration of production-db requires restart of whole stack of containers.
docker container networks? more commandlines though. can't add db alias on the run command.