fix bugs

migrations/mysql/02105_node.sql

@@ -1,4 +1,3 @@
--- migrate:up
 CREATE TABLE IF NOT EXISTS `servers` (
         `id` bigint NOT NULL AUTO_INCREMENT,
         `name` varchar(100) COLLATE utf8mb4_general_ci NOT NULL DEFAULT '' COMMENT 'Server Name',
@@ -28,7 +27,3 @@ CREATE TABLE IF NOT EXISTS `nodes` (
      PRIMARY KEY (`id`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
 
--- migrate:down
-DROP TABLE IF EXISTS `nodes`;
-DROP TABLE IF EXISTS `servers`;
-