Add note about reloading vagrant after .yaml change

Author: ps

homestead.md

@@ -111,6 +111,8 @@ You can make any Homestead site use [HHVM](http://hhvm.com) by setting the `hhvm
           to: /home/vagrant/Code/Laravel/public
           hhvm: true
 
+Note that whenever the `sites` property is altered it may be necessary to run `vagrant reload --provision` in order for the Homestead environment, or in particular the Nginx configuration file in `/etc/nginx/sites-enabled`, to be refreshed accordingly.
+
 #### The Hosts File
 
 You must add the "domains" for your Nginx sites to the `hosts` file on your machine. The `hosts` file will redirect requests for your Homestead sites into your Homestead machine. On Mac and Linux, this file is located at `/etc/hosts`. On Windows, it is located at `C:\Windows\System32\drivers\etc\hosts`. The lines you add to this file will look like the following: