Fixed error in mysql migration

composer.json

@@ -1,6 +1,6 @@
 {
   "name": "sergix44/xbackbone",
-  "version": "3.0",
+  "version": "3.0.1",
   "description": "A lightweight ShareX PHP backend",
   "type": "project",
   "require": {

resources/schemas/mysql/mysql.4.sql

@@ -1,7 +1,7 @@
 ALTER TABLE `users`
-    ADD COLUMN `remember_selector` VARCHAR(16),
-    ADD COLUMN `remember_token` VARCHAR(256),
-    ADD COLUMN `remember_expire` TIMESTAMP;
+    ADD COLUMN `remember_selector` VARCHAR(16) DEFAULT NULL,
+    ADD COLUMN `remember_token` VARCHAR(256) DEFAULT NULL,
+    ADD COLUMN `remember_expire` TIMESTAMP NULL DEFAULT NULL;
 
 ALTER TABLE `users` ADD INDEX (`remember_selector`);