text: --notifications (up)
  create table notifications
  (
      id uuid not null,
      title text not null,
      summary text,
      created_at timestamp default CURRENT_TIMESTAMP,
      read_at timestamp,
      site_id int not null,
      user_id int not null,
      action_id text not null,
      action_link text,
      action_text text,
      from_user_id int,
      from_user_name text,
      thumbnail text,
      tags text[]
  );
  
  create unique index notifications_id_uindex
      on notifications (id);
  
  create index notifications_site_id_user_id_created_at_index
      on notifications (site_id asc, user_id asc, created_at desc);
  
  alter table notifications
      add constraint notifications_pk
          primary key (id);
  
  