Fix docker-compose for DokPloy compose deployment

Use .env instead of outline.env, reference existing named volumes
as external so data persists across DokPloy redeploys.

docker-compose.yml

@@ -16,7 +16,8 @@ services:
     image: docker.getoutline.com/outlinewiki/outline:latest
     container_name: outline
     restart: unless-stopped
-    env_file: ./outline.env
+    env_file:
+      - .env
     depends_on:
       postgres:
         condition: service_healthy
@@ -73,5 +74,11 @@ networks:
 
 volumes:
   outline-storage:
+    name: code_outline-storage
+    external: true
   postgres-data:
+    name: code_postgres-data
+    external: true
   redis-data:
+    name: code_redis-data
+    external: true