public async Task <IActionResult> Index()
        {
            NewsletterModel newsletterModel = await NewsletterRepository.GetAsync();

            List <ObjectNewsletter> newsletterList = new List <ObjectNewsletter>(newsletterModel.data.Capacity);

            newsletterList.AddRange(newsletterModel.data);
            return(PartialView(new NewsletterViewModel(newsletterList)));
        }