text: -- 商品评论
  CREATE TABLE `commodity_comment` (
    `id` BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `product_id` BIGINT NOT NULL COMMENT '商品ID',
    `user_id` BIGINT NOT NULL COMMENT '用户ID',
    `user_nickname` VARCHAR(32) NOT NULL COMMENT '用户在本站的昵称',
    `comment` VARCHAR(255) NOT NULL COMMENT '评论内容',
    `create_at` DATETIME NOT NULL COMMENT '评论时间',
    `reply_count` INT DEFAULT 0 COMMENT '这条评论回复数'
  )
  COLLATE='utf8_unicode_ci'
  ENGINE=InnoDB
  ;