Add Docker Compose stack for L2 Essence 542 with PostgreSQL 17 and install scripts.

docker/initdb/02_grant_app_user.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+# Выдаёт владельца таблиц логина роли из POSTGRES_USER (см. docker-compose).
+set -eu
+psql -v ON_ERROR_STOP=1 --username "postgres" --dbname "$POSTGRES_DB" <<-EOSQL
+ALTER TABLE IF EXISTS accounts OWNER TO "${POSTGRES_USER}";
+ALTER TABLE IF EXISTS account_data OWNER TO "${POSTGRES_USER}";
+ALTER TABLE IF EXISTS gameservers OWNER TO "${POSTGRES_USER}";
+EOSQL