Move MySQL comments to MySQL forge classes only
diff --git a/system/database/drivers/mysql/mysql_forge.php b/system/database/drivers/mysql/mysql_forge.php
index ee89e1d..282e2d1 100644
--- a/system/database/drivers/mysql/mysql_forge.php
+++ b/system/database/drivers/mysql/mysql_forge.php
@@ -185,6 +185,8 @@
 			$extra_clause = ' FIRST';
 		}
 
+		$comment_clause = isset($field['comment']) ? ' COMMENT ' . $field['comment'] : '';
+
 		return $this->db->escape_identifiers($field['name'])
 			.(empty($field['new_name']) ? '' : ' '.$this->db->escape_identifiers($field['new_name']))
 			.' '.$field['type'].$field['length']
@@ -193,7 +195,7 @@
 			.$field['default']
 			.$field['auto_increment']
 			.$field['unique']
-			.$field['comment']
+			.$comment_clause
 			.$extra_clause;
 	}