Added new modes to README

Author: Richard Stempfl

README.md

@@ -35,15 +35,15 @@ should be a dict containing the following items:
 `libvirt_host_networks` is a list of networks to define and start. Each item
 should be a dict containing the following items:
 - `name` The name of the network.
-- `mode` The forwarding mode of the network, `bridge`, `route` and `nat` are
-  supported.
+- `mode` The forwarding mode of the network, `bridge`, `route`, `open` and `nat` are
+  supported. Leave empty for a isolated network mode.
 - `bridge` The name of the bridge interface for this network.
-- `ip` IP address of the virtual bridge, mandatory for `route` and `nat` mode.
-- `netmask` Netmask of the virtual bridge, mandatory for `route` and `nat` mode.
-- `domain` DNS domain name for `route` and `nat` mode, default to the network
+- `ip` IP address of the virtual bridge, mandatory for `route`, `open` and `nat` mode.
+- `netmask` Netmask of the virtual bridge, mandatory for `route`, `open` and `nat` mode.
+- `domain` DNS domain name for `route`, `open` and `nat` mode, default to the network
    name (optional).
-- `dhcp_start` First IP of the DHCP range in `route` or `nat` mode (optional).
-- `dhcp_end` Last IP of the DHCP range in `route` or `nat` mode (optional).
+- `dhcp_start` First IP of the DHCP range in `route` , `open` or `nat` mode (optional).
+- `dhcp_end` Last IP of the DHCP range in `route`, `open` or `nat` mode (optional).
 - `routes` Optional list of additionals routes defined as following:
   - `address` Address of the route, required.
   - `prefix` Prefix of the route, required.