Create kngil DB in init shell script

docker/initdb/00_create_db.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+set -e
+
+psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --dbname "postgres" <<'EOSQL'
+DO $$
+BEGIN
+  IF NOT EXISTS (SELECT 1 FROM pg_database WHERE datname = 'kngil') THEN
+    CREATE DATABASE kngil;
+  END IF;
+END
+$$;
+EOSQL