text: -- +migrate Up
  create table tag (
      id bigint not null primary key,
      value varchar(255)
  );
  create table product_tag (
      tag_id bigint not null,
      product_id bigint not null,
      value varchar(255) not null,
      foreign key (tag_id) references tag(id) on delete cascade,
      foreign key (product_id) references product(id) on delete cascade,
      constraint pk_product_tag primary key (tag_id, product_id)
  );
  -- +migrate Down
  drop table product_tag;
  drop table tag;