CREATE TABLE IF NOT EXISTS `users` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `username` VARCHAR(255) NOT NULL,
  `email` VARCHAR(255) NOT NULL,
  `password_hash` VARCHAR(255) NOT NULL,
  `created_at` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  UNIQUE KEY `username` (`username`),
  UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;