Minor - Adding docs.

main/inc/lib/chamilo_session.class.php

@@ -1,10 +1,13 @@
 <?php
+/* For licensing terms, see /license.txt */
 
 /**
  * ChamiloSession class definition
+ * @todo just the Session from the Symfony2 component
  */
 class ChamiloSession
 {
+    /** @var Symfony\Component\HttpFoundation\Session\Session */
     public static $session;
 
     /**
@@ -67,7 +70,7 @@ class ChamiloSession
     }
 
     /**
-     *
+     * Invalidate the session.
      */
     public static function destroy()
     {