I'm learning to use docker, there is something I don't get it. The Etherpad Lite image for docker links the mysql db like this :$ docker network create ep_network $ docker run -d --network  ep_network -e MYSQL_ROOT_PASSWORD=password --name ep_mysql mysqlFinally you can start an instance of Etherpad Lite:$ docker run -d \      --network ep_network \      -e ETHERPAD_DB_HOST=ep_mysql \      -e ETHERPAD_DB_PASSWORD=password \      -p 9001:9001 \      tvelocity/etherpad-liteis it possible to do the same with the option, add link to another container --link, by linking  ep_mysql to the etherpad's docker ? like the odoo container do :Start a PostgreSQL server$ docker run -d -e POSTGRES_USER=odoo -e POSTGRES_PASSWORD=odoo --name  db postgres:9.4Start an Odoo instance$ docker run -p 8069:8069 --name odoo --link db:db -t odooso why Etherpad uses docker network and why odoo uses --link ?in wich case(s) I should use the first way instead of the second one ?some dockers have no information on the hub/store, so how can I figure how I have to link containers ?
Why some dockers use docker network instead of the link parameter?
docker