chore(docker/postgres.yml): add example on how to run with prod profile.

Addressed to #1034

[skip ci]

Author: php-coder

docker/postgres.yml

@@ -15,6 +15,8 @@ services:
       - SPRING_DATASOURCE_USERNAME=mystamps
       - SPRING_DATASOURCE_PASSWORD=secret
       - SPRING_DATASOURCE_DRIVER_CLASS_NAME=org.postgresql.Driver
+      # to test whether it works in prod-like environment
+      #- LIQUIBASE_CONTEXTS=scheme,init-data,prod-data
     networks:
       - internal-network
     depends_on: