docs: fix universal dep save flag

justingrayston · dond2clouds · commit 6c607ecbce6a · 2018-04-23T13:34:39.000-05:00
Closes angular#7211
diff --git a/docs/documentation/stories/universal-rendering.md b/docs/documentation/stories/universal-rendering.md
@@ -13,7 +13,7 @@ $ npm install --save-dev @angular/platform-server
 ```
 or
 ```bash
-$ yarn add @angular/platform-server
+$ yarn add @angular/platform-server --dev
 ```
 
 
