private async Task PopulateCategories()
{
var categoriesFirstLevel = _data.CategoriesFirstLevel();
await SaveRange(categoriesFirstLevel);
await PopulateUrlRecordsFor(categoriesFirstLevel);
var categoriesSecondLevel = _data.CategoriesSecondLevel();
await SaveRange(categoriesSecondLevel);
await PopulateUrlRecordsFor(categoriesSecondLevel);
}