public bool Delete(Student student)
        {
            context.Studenten.Remove(student);
            context.SaveChanges();

            return true;
        }
 public void Edit(Student student)
 {
     context.Entry(student).State = EntityState.Modified;
     context.SaveChanges();
 }
 public void AddUserId(Student student, string id)
 {
     student.UserId = id;
     context.Entry(student).State = EntityState.Modified;
     context.SaveChanges();
 }
 public void Add(Student student)
 {
     studenten.Add(student);
 }