docs(www): Update npm run serve description (#11993)

andrecalvo · sidharthachatterjee · commit 11ad02b02112 · 2019-02-22T19:57:42.000+05:30
diff --git a/docs/docs/quick-start.md b/docs/docs/quick-start.md
@@ -48,7 +48,7 @@ Gatsby will perform an optimized production build for your site, generating stat
 npm run serve
 ```
 
-Gatsby starts a local HTML server for testing your built site.
+Gatsby starts a local HTML server for testing your built site. Remember to build your site using `npm run build` before using this command.
 
 ### Access documentation for CLI commands.
 
