impl<T> Paginated<T> {
    pub fn load_page<U: Serialize>(self, conn: &PgConnection) -> QueryResult<Page<U>>
    where
        Self: LoadQuery<PgConnection, U>,
        T: SelectDsl<_>
    {
        use diesel::dsl::count_star;
        let total = self.query.select(count_star()).first(conn)?;
        let items = self.load::<U>(conn)?;
        Ok(Page{items, total})
    }
}