Adjust a few phpdoc in query builder code
diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index e6a1082..fb314e5 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -1138,7 +1138,7 @@
 	 * ORDER BY
 	 *
 	 * @param	string	$orderby
-	 * @param	string	$direction	ASC or DESC
+	 * @param	string	$direction	ASC, DESC or RANDOM
 	 * @param	bool	$escape
 	 * @return	CI_DB_query_builder
 	 */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
index d0cdde2..83daee9 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
@@ -166,7 +166,7 @@
 	 * ORDER BY
 	 *
 	 * @param	string	$orderby
-	 * @param	string	$direction	ASC or DESC
+	 * @param	string	$direction	ASC, DESC or RANDOM
 	 * @param	bool	$escape
 	 * @return	object
 	 */
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
 	 */