Docker image network choice
Description
As --link is named as old behavior for docker, what about creating custom network for all builds, or ability to choose network from .gitlab-ci.yml?
For example, if I want to use persistent service (for example, same postgres database for old builds, check migrations for persistent database, or same), now I need to run this persistent service separately, save its IP address, and, after that, hack /etc/hosts with its IP.
Proposal
Add something like: network: custom-created-network to .gitlab-ci.yml and start build containers with --network=$CI_NETWORK argument for easy linking containers by name