Mount pgdata at the directory Postgres 18 actually uses

docker-compose.yml

@@ -5,11 +5,10 @@ services:
       POSTGRES_USER: levyraati
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:?set POSTGRES_PASSWORD in .env}
       POSTGRES_DB: levyraati
-      # The 18 image moved its default data directory; pin it so the ./pgdata mount below
-      # is still where the database lives.
-      PGDATA: /var/lib/postgresql/data
     volumes:
-      - ./pgdata:/var/lib/postgresql/data
+      # Postgres 18 keeps its data in /var/lib/postgresql/<version>/docker, so the mount is the
+      # parent directory, not the old /var/lib/postgresql/data.
+      - ./pgdata:/var/lib/postgresql
     healthcheck:
       test: ["CMD-SHELL", "pg_isready -U levyraati"]
       interval: 5s