added more info within readme

readme.md

@@ -2,6 +2,67 @@
 
  nodast is (for now) an Asterisk FastAGI reverse proxy on [node](http://nodejs.org).
 
+## How It Works
+
+ nodast receives FastAGI requests from asterisk (or other nodast as a matter of fact), inspect incoming stream for AGI request details.
+ Looking more specifically at the agi_request parameter, the AGI URL is then matched against the config route definitions, where route definitions
+ values are either static or dynamic. Dynamic values are simply JavaScript closure blocks, with /this/ pointing to a variable context 
+ containing all request parameters along with regexp match group items. The dynamic function is simply rewriting the AGI URL, changing
+ the destination hostname and port as necessary. The resulting route is NOT re-injected into   
+
+ Once route has been resolved, nodast then look for upstream definitions and replace logical name with upstream equivalent.
+
+## Context Variables
+
+The follow list all available context variable for dynamic route definition.
+
+    $network_script
+    $request
+    $channel
+    $language
+    $type
+    $uniqueid
+    $version
+    $callerid
+    $calleridname
+    $callingpres
+    $callingani2
+    $callington
+    $callingtns
+    $dnid
+    $rdnis
+    $context
+    $extension 
+    $priority
+    $enhanced
+    $accountcode
+    $threadid
+
+## Sample Configuration
+
+ var config = {
+    listen : 9090,
+    upstreams : {
+        test : 'localhost:4573',
+        foobar : 'foobar.com:4573'
+    },
+    routes : {
+        'agi://(.*):([0-9]*)/(.*)' : function() {
+            if (this.$callerid === 'unknown') {
+                return ('agi://foobar/script/' + this.$3);
+            } else {
+                return ('agi://foobar/script/' + this.$3 + '?callerid' + this.$callerid);
+            }
+        },
+        '.*' : function() {
+            return ('agi://test/');
+        },
+        'agi://192.168.129.170:9090/' : 'agi://test/'
+    }
+ };
+
+ exports.config = config; 
+
 ## Features
 
   * Basic config definition with location and upstream
@@ -16,8 +77,9 @@ Install from npm:
 
 ## Todo
 
-  * Add load balancing support between upstream
-  * Add failover
+  * Add to npm repository
+  * Add load balancing support between upstreams
+  * Add failover/backup upstream
   * Add SSL/TLS support between node (asterisk -> node -> ssl -> node -> fastagi server
   * Add support for AMI
   * Scriptable?