chore(configuration.md): update .env.example

Author: chekist32

docs/getting-started/configuration.md

@@ -10,17 +10,17 @@ Here you can see an example .env file:
 # In 'dev' mode, a reflection server is established.
 MODE=dev
 
-SERVER_HOST=localhost
+SERVER_HOST=0.0.0.0
 SERVER_PORT=3000
 
 # As for now, only PostgreSQL is supported
-DATABASE_HOST=localhost
-DATABASE_PORT=54321
+DATABASE_HOST=db
+DATABASE_PORT=5432
 DATABASE_USER=postgres
 DATABASE_PASS=postgres
 DATABASE_NAME=goipay_db
 
 XMR_DAEMON_URL=http://node.monerodevs.org:38089
 XMR_DAEMON_USER=
 XMR_DAEMON_PASS=
-```
+```