text: CREATE TABLE `users` (
    `id` bigint(20) NOT NULL AUTO_INCREMENT,
    `name` varchar(40) NOT NULL,
    `username` varchar(15) NOT NULL,
    `email` varchar(40) NOT NULL,
    `password` varchar(100) NOT NULL,
    `created_at` timestamp DEFAULT CURRENT_TIMESTAMP,
    `updated_at` timestamp DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (`id`),
    UNIQUE KEY `uk_users_username` (`username`),
    UNIQUE KEY `uk_users_email` (`email`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
  
  
  CREATE TABLE `roles` (
    `id` bigint(20) NOT NULL AUTO_INCREMENT,
    `name` varchar(60) NOT NULL,
    PRIMARY KEY (`id`),
    UNIQUE KEY `uk_roles_name` (`name`)
  ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;
  
  
  CREATE TABLE `user_roles` (
    `user_id` bigint(20) NOT NULL,
    `role_id` bigint(20) NOT NULL,
    PRIMARY KEY (`user_id`,`role_id`),
    KEY `fk_user_roles_role_id` (`role_id`),
    CONSTRAINT `fk_user_roles_role_id` FOREIGN KEY (`role_id`) REFERENCES `roles` (`id`),
    CONSTRAINT `fk_user_roles_user_id` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
  
  CREATE TABLE `cities` (
    `id` bigint(20) NOT NULL AUTO_INCREMENT,
    `name` varchar(60) NOT NULL,
    PRIMARY KEY (`id`),
    UNIQUE KEY `uk_cities_name` (`name`)
  ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
  
  
  CREATE TABLE `polls` (
    `id` bigint(20) NOT NULL AUTO_INCREMENT,
    `question` varchar(140) NOT NULL,
    `expiration_date_time` datetime NOT NULL,
    `created_at` timestamp DEFAULT CURRENT_TIMESTAMP,
    `updated_at` timestamp DEFAULT CURRENT_TIMESTAMP,
    `created_by` bigint(20) DEFAULT NULL,
    `updated_by` bigint(20) DEFAULT NULL,
    PRIMARY KEY (`id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
  
  
  CREATE TABLE `choices` (
    `id` bigint(20) NOT NULL AUTO_INCREMENT,
    `text` varchar(40) NOT NULL,
    `poll_id` bigint(20) NOT NULL,
    PRIMARY KEY (`id`),
    KEY `fk_choices_poll_id` (`poll_id`),
    CONSTRAINT `fk_choices_poll_id` FOREIGN KEY (`poll_id`) REFERENCES `polls` (`id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
  
  
  CREATE TABLE `votes` (
    `id` bigint(20) NOT NULL AUTO_INCREMENT,
    `user_id` bigint(20) NOT NULL,
    `poll_id` bigint(20) NOT NULL,
    `choice_id` bigint(20) NOT NULL,
    `created_at` timestamp DEFAULT CURRENT_TIMESTAMP,
    `updated_at` timestamp DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (`id`),
    KEY `fk_votes_user_id` (`user_id`),
    KEY `fk_votes_poll_id` (`poll_id`),
    KEY `fk_votes_choice_id` (`choice_id`),
    CONSTRAINT `fk_votes_user_id` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`),
    CONSTRAINT `fk_votes_poll_id` FOREIGN KEY (`poll_id`) REFERENCES `polls` (`id`),
    CONSTRAINT `fk_votes_choice_id` FOREIGN KEY (`choice_id`) REFERENCES `choices` (`id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
  