Make postgres directory as external

docker-compose.yml

@@ -15,7 +15,7 @@ services:
     # Use "command: postgres -c jit=off" for PostgreSQL 11+ because of slow large MVT query processing
     # Use "shm_size: 512m" if you want to prevent a possible 'No space left on device' during 'make generate-tiles-pg'
     volumes:
-      - pgdata:/var/lib/postgresql/data
+      - /data/openmaptiles/postgresql:/var/lib/postgresql/data
     networks:
       - postgres
     ports: