text: do $$
  begin
    if not exists (select 1 from "pg_type" where "typname" = 'setting_key') then
      create type "setting_key" as enum('AllowRegistration', 'DefaultNewUserRole');
    end if;
  end$$;
  
  create table if not exists "setting_values" (
    "k" setting_key primary key,
    "v" character varying(4096) not null
  );
  