private string Enrollments()
        {
            var enrollments = db.Enrollments
                              .Include(e => e.User)
                              .Include(e => e.IMSClass)
                              .Include(e => e.School);

            var sb = new StringBuilder();

            using (var csv = new CsvWriter(new StringWriter(sb)))
            {
                Enrollment.CsvHeader(csv);
                foreach (var enrollment in enrollments)
                {
                    enrollment.AsCsvRow(csv);
                }
                return(sb.ToString());
            }
        }