text: -- add_subscription adds the provided subscription to the database.
  create or replace function add_subscription(p_subscription jsonb)
  returns void as $$
      insert into subscription (
          user_id,
          package_id,
          event_kind_id
      ) values (
          (p_subscription->>'user_id')::uuid,
          (p_subscription->>'package_id')::uuid,
          (p_subscription->>'event_kind')::int
      );
  $$ language sql;
  