text: create table user
  (
      id            varchar(40)                         not null    primary key,
      username      varchar(128)                        not null,
      email         varchar(128)                        not null,
      password      varchar(128)                        not null,
      register_time timestamp default CURRENT_TIMESTAMP not null,
      constraint user_email_uindex unique (email),
      constraint user_username_uindex unique (username)
  );