CREATE TABLE IF NOT EXISTS `community_members` (
  `id` INT AUTO_INCREMENT PRIMARY KEY,
  `user_id` INT NOT NULL,
  `community_id` INT NOT NULL,
  `created_at` TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  FOREIGN KEY (`user_id`) REFERENCES `users`(`id`),
  FOREIGN KEY (`community_id`) REFERENCES `communities`(`id`)
);