public async Task <IActionResult> EditStudents(int courseId)
        {
            var course   = _coursesRepository.GetById(courseId);
            var students = await _studentsRepository.GetActiveStudents();

            var subjectId = course.SubjectId;
            var subject   = _subjectsRepository.GetById(subjectId);

            var model = new CourseEditStudentsViewModel
            {
                CourseId = courseId,

                Course = new CourseViewModel
                {
                    CourseId    = courseId,
                    Description = subject.Description,
                    Start       = course.StartDate,
                    End         = course.EndDate,
                    Subject     = subject,
                    Name        = course.Name,
                    Teacher     = new UserViewModel
                    {
                        Email      = course.Teacher.Email,
                        FirstName  = course.Teacher.FirstName,
                        LastName   = course.Teacher.LastName,
                        MiddleName = course.Teacher.MiddleName,
                    },
                    TeacherId = course.TeacherId,
                    SubjectId = subjectId
                },
            };

            var studentsInCourse = (await _coursesRepository.GetStudents(model.CourseId)).Select(x => x.StudentId).ToList();

            model.Students = students.Select(x => new CourseStudentEditViewModel
            {
                Id       = x.StudentId,
                Name     = x.User.LastName + " " + x.User.FirstName + " " + x.User.MiddleName,
                Selected = studentsInCourse.Count == 0 ? false : studentsInCourse.Contains(x.StudentId)
            }).ToList();

            return(View(model));
        }