public Res AddStudent(aspnet_Users student, Group group, ModelContainer data)
        {
            bool Success = true;
            IEnumerable<Group> groups = null;
            try
            {
                foreach (Group g in student.Groups)
                   g.aspnet_Users.Remove(student);

                group.aspnet_Users.Add(student);
                data.SaveChanges();
            }
            catch (Exception e)
            {
                Success = false;
            }
            return new Res(Success, groups);
        }
        public Res CreateRequest(aspnet_Users user, Group group, ModelContainer data)
        {
            bool Success = true;
            IEnumerable<StudentRequest> requests = null;
            //try
               // {
                StudentRequest request = data.StudentRequests.Create();
                request.StudentRequestId = Guid.NewGuid();
                request.aspnet_Users = user;
                request.Message = "m";
                request.Group = group;
                data.StudentRequests.Add(request);
                data.SaveChanges();
               // }
               // catch (Exception e)
               // {
                //Success = false;
               // }

            return new Res(Success, requests);
        }