Updated README to list attributes and give a little more help

README.md

@@ -19,11 +19,17 @@ Debian or Ubuntu - it may work where 'build-essential' works, but other platform
 Attributes
 ==========
 
-* conf_path - location to drop the Nginx config files
+* conf_dir - location to drop the Nginx config files. Default is based on platform.
+* listen_port - Port for the Nginx server to listen on.  default is 80
+* server_name - Server name for the proxy to listen on - default is www.example.com
+* destination_url - Destination for proxied connections - default is http://127.0.0.1
 
 Usage
 =====
 
 Intended to be a skeleton to quickly spin up an Nginx proxy server. The first use case
 will be a simple forwarding proxy, both with and without caching. However, this 
 should be relatively simple to build upon.
+
+Note - the defaults are meant to be overridden in roles or elsewhere - they are not
+particularly useful other than to allow the nginx server to start.