public void SaveFromJson(string json)
 {
     var ctx = new LinqToSqlXml.DocumentContext("main");
     ctx.GetCollection<Customer>().Add(json);
     ctx.SaveChanges();
 }
 public void Save(Customer customer)
 {
     var ctx = new LinqToSqlXml.DocumentContext("main");
     ctx.GetCollection<Customer>().Add(customer);
     ctx.SaveChanges();
 }