diff --git a/docker/brook/README.md b/docker/brook/README.md
index 9cf62d6..96c802c 100644
--- a/docker/brook/README.md
+++ b/docker/brook/README.md
@@ -22,6 +22,7 @@ It can be found at [Docker Hub][4].
 ## Start a container
 
 You **must set environment variable** `ARGS` at first.
+
 There is an example to start a container that listen on port `9000`, password is `password0` (both TCP and UDP) run as a brook server like below:
 
 ```bash