diff --git a/docs/operators/tutorial.md b/docs/operators/tutorial.md
index 2e6f7df..beec588 100644
--- a/docs/operators/tutorial.md
+++ b/docs/operators/tutorial.md
@@ -109,7 +109,7 @@ You need to keep port `:80` and `:443` free on your server for web proxying to y
 wget -O- https://get.docker.com | bash
 
 # add user to docker group
-usermod -aG docker $USER
+sudo usermod -aG docker $USER
 
 # setup swarm
 docker swarm init