pull previous build

.drone.yml

@@ -5,10 +5,11 @@ pipeline:
      - cp nginx.conf /etc/nginx/
      - nginx -t
  docker:
-    image: plugins/docker
+    image: repo.shimun.net/drone-docker
     repo: repo.shimun.net/shimun/seafile
     registry: repo.shimun.net
     storage_path: /drone/.docker
     secrets: ["docker_username", "docker_password"]
     storage_path: /drone/.docker
+    pull_previous: true
     use_cache: true