[#12048] Add SQL description for postgres config

src/main/resources/build-dev.template.properties

@@ -14,7 +14,7 @@ app.frontend.url = http\://localhost:4200
 # This is the port to connect with local Datastore emulator.
 app.localdatastore.port = 8484
 
-# Configurations for postgres
+# Default configurations for the local Postgres instance details on Docker. No further changes will be needed.
 app.postgres.host=localhost
 app.postgres.port=5432
 app.postgres.databasename=teammates

src/main/resources/build.template.properties

@@ -32,6 +32,11 @@ app.version = 8-0-0
 app.postgres.host=
 app.postgres.port=5432
 app.postgres.databasename=postgres
+
+# For production purposes, a separate role with less privileges (i.e unable to drop tables) should be created
+# instead of using superadmin postgres.
+# app.postgres.username=production_user
+# For staging purposes, logging in as postgres will do.
 app.postgres.username=postgres
 app.postgres.password=