Update with sock index.js

lib/index.js

@@ -42,10 +42,17 @@ class AgiServer extends EventEmitter {
       this.emit('error', new Error('Internal TCP server error'));
     });
     this.server.on('close', () => this.emit('close'));
-
-    this.server.listen(this.options.port, this.options.host, () => {
-      console.log('agi server on', this.options.port, 'listen');
-    });
+    
+    if(this.options.host){
+        this.server.listen(this.options.port, this.options.host, () => {
+          console.log('agi server on', this.options.port, 'listen');
+        });
+    }
+    else{
+        this.server.listen(this.options.port, () => {
+          console.log('agi server on', this.options.port, 'listen');
+        });
+    }
   }
 
   /**