Merge pull request #628 from kridolfo/patch-1

Added links to the user guide for Encryption class and Session class.
diff --git a/application/config/config.php b/application/config/config.php
index 808cc33..063c3d5 100644
--- a/application/config/config.php
+++ b/application/config/config.php
@@ -253,6 +253,9 @@
 |
 | If you use the Encryption class or the Session class you
 | MUST set an encryption key.  See the user guide for info.
+|  
+| http://codeigniter.com/user_guide/libraries/encryption.html
+| http://codeigniter.com/user_guide/libraries/sessions.html
 |
 */
 $config['encryption_key'] = '';