public function initCategories($overrideExisting = true)
    {
        if (null !== $this->collCategories && !$overrideExisting) {
            return;
        }

        $collectionClassName = CategoryTableMap::getTableMap()->getCollectionClassName();

        $this->collCategories = new $collectionClassName;
        $this->collCategories->setModel('\Attogram\SharedMedia\Orm\Category');
    }