Update README.md

Author: sgsullivan

README.md

@@ -53,7 +53,7 @@ docker-machine {restart|start|stop} docker01
 Create a new compute node with template `UBUNTU_2004_UNMANAGED` (overriding the default)
 
 ```shell
-user@host $ docker-machine create docker04 --driver liquidweb --lw-template UBUNTU_2004_UNMANAGED 
+user@host $ docker-machine create docker04 --driver liquidweb --lw-template UBUNTU_2004_UNMANAGED --lw-zone-id 12
 Running pre-create checks...
 (docker04) Generating a random root password...
 Creating machine...