Merge pull request #439 from toshi38/stelau/fix-readme-drop-user

Breakup USER and comment to two lines.
diff --git a/README.md b/README.md
index 3f2fbb3..78b37ff 100644
--- a/README.md
+++ b/README.md
@@ -138,7 +138,8 @@
 # if we want to install via apt
 USER root
 RUN apt-get update && apt-get install -y ruby make more-thing-here
-USER jenkins # drop back to the regular jenkins user - good practice
+# drop back to the regular jenkins user - good practice
+USER jenkins
 ```
 
 In such a derived image, you can customize your jenkins instance with hook scripts or additional plugins.