public async Task AddNewsletter(string email)
        {
            if (_repo
                .FindBy(e => e.Email.Equals(email))
                .FirstOrDefault() == null)
            {
                await _repo.Create(new Models.Newsletter()
                {
                    Email   = email,
                    AddedOn = DateTime.Now
                });

                await _unitOfWork.Commit();
            }
        }