public FileContentResult DownloadEmailList()
        {
            var users      = _volunteerRepository.FindAll().Where(x => x.HasCancelled == false).Select(x => x.Email).Distinct();
            var notTechies = _nonTechieVolunteerRepository.FindAll().Where(x => x.HasCancelled == false).Select(x => x.Email).Distinct();

            var sb = new StringBuilder();

            foreach (var user in users)
            {
                sb.AppendFormat(user + ",");
            }

            foreach (var notTechy in notTechies)
            {
                sb.AppendFormat(notTechy + ",");
            }

            return(File(new UTF8Encoding().GetBytes(sb.ToString()), "text/csv", "UserMailAddress.csv"));
        }