adding sanitize_filename() into the security helper
diff --git a/user_guide/helpers/security_helper.html b/user_guide/helpers/security_helper.html
index 97be674..f74a776 100644
--- a/user_guide/helpers/security_helper.html
+++ b/user_guide/helpers/security_helper.html
@@ -75,6 +75,12 @@
<a href="../libraries/input.html">Input class</a>. More info can be found there.</p>
+<h2>sanitize_filename()</h2>
+
+<p>Provides protection against directory traversal. This function is an alias to the one in the
+<a href="../libraries/security.html">Security class</a>. More info can be found there.</p>
+
+
<h2>do_hash()</h2>
<p>Permits you to create SHA1 or MD5 one way hashes suitable for encrypting passwords. Will create SHA1 by default. Examples:</p>