Update 'README.md'

README.md

@@ -50,6 +50,15 @@ Start XFCE, you run it only once.
 startxfce4
 ```
 
+If you're using USB tethering or you don't have an easy access to the Ethernet you need to uncomment the following string with `sudo vim /etc/network/interfaces` and add `auto usb0`:
+
+```
+### Mobile tether
+auto usb0
+allow-hotplug usb0
+iface usb0 inet dhcp
+```
+
 # HushChat
 
 # Tor