add session table

broker/migrate/mysql/V13__create_session_table.sql

@@ -0,0 +1,14 @@
+
+DROP TABLE IF EXISTS `t_session`;
+CREATE TABLE `t_session` (
+  `row_id` varchar(50) not null primary key,
+  `del_flag` tinyint(1) default 0 null,
+  `create_time` timestamp null,
+  `update_time` timestamp null,
+  `expire_time` timestamp null,
+  `user_id` int null,
+  constraint `t_session_pk_2` unique (`user_id`, `expire_time`)
+)
+ENGINE = InnoDB
+DEFAULT CHARACTER SET = utf8mb4
+COLLATE = utf8mb4_unicode_ci;