fix: wrong migration query

Author: riflowth

other/db/migrations/000005_fix_update_testcase_issue.down.sql

@@ -3,4 +3,4 @@ ALTER TABLE `submission_result`
 ALTER TABLE `submission_result`
   ADD CONSTRAINT `submission_result_ibfk_2` FOREIGN KEY (`testcase_id`) REFERENCES `testcase`(`id`) ON DELETE CASCADE;
 
-ALTER TABLE `testcase` ADD `revision` INT NOT NULL AFTER `assignment_id`;
+ALTER TABLE `testcase` DROP COLUMN `revision`;

other/db/migrations/000005_fix_update_testcase_issue.up.sql

@@ -3,4 +3,4 @@ ALTER TABLE `submission_result`
 ALTER TABLE `submission_result`
   ADD CONSTRAINT `submission_result_ibfk_2` FOREIGN KEY (`testcase_id`) REFERENCES `testcase`(`id`);
 
-ALTER TABLE `testcase` DROP COLUMN `revision`;
+ALTER TABLE `testcase` ADD `revision` INT NOT NULL AFTER `assignment_id`;