public function votes($class = __CLASS__)
    {
        return $this->morphedByMany($class, config('follow.morph_prefix'), config('follow.followable_table'))
                    ->wherePivotIn('relation', [Follow::RELATION_UPVOTE, Follow::RELATION_DOWNVOTE])
                    ->withPivot('followable_type', 'relation', 'created_at');
    }