README.md in gemirro-0.10.5 vs README.md in gemirro-0.11.0

@@ -39,9 +39,10 @@
 
 Once all the Gems have been downloaded you'll need to generate an index of all the installed files. This can be done as following:
 
 ```bash
 $ gemirro index
+$ gemirro index --update # Or only update new files
 ```
 
 Last, launch the server, and all requests will check if gems are detected, and download them if necessary and generate index immediately.
 
 ```bash