public string NewsLetter(string newsletter)
        {
            if (newsletter == "null" || newsletter == "")
            {
                return("erro");
            }

            try
            {
                var news = new Newsletter
                {
                    Email = newsletter,
                    Ativo = true
                };

                _newsletterService.Inserir(news);
                return("ok");
            }
            catch (Exception)
            {
                return("erro");
            }
        }