public function update()
    {
        $this->apply(function ($config) {
            $foreignKey = snake_case($this->key($config['foreignKey']));
            $amount = $this->model->{$config['columnToSum']};

            if ($this->model->getOriginal($foreignKey) && $this->model->{$foreignKey} != $this->model->getOriginal($foreignKey)) {
                $this->updateCacheRecord($config, '-', $amount, $this->model->getOriginal($foreignKey));
                $this->updateCacheRecord($config, '+', $amount, $this->model->{$foreignKey});
            }
        });
    }