CHECK constraints are a powerful way to control data stored in a SQL database. Combined with choosing the appropriate type for we can enforce that the data written adheres to our business rules.
Connecting to a dockerised postgres instance via psql using user-defined bridge networks
Docker containers can communicate with each other either using the deprecated links machinery or using user-defined networks. The latter also is the way to go when using docker-compose since a user-defined network is created by default (at least in recent versions).