Adjust a few phpdoc in query builder code
diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index ac7345a..f24db46 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -512,7 +512,7 @@
 	 * ORDER BY
 	 *
 	 * @param	string	$orderby
-	 * @param	string	$direction	ASC or DESC
+	 * @param	string	$direction	ASC, DESC or RANDOM
 	 * @param	bool	$escape
 	 * @return	object
 	 */