public void AddAssistantToCourse(int AssistantId, int CourseId, string ClassType)
        {
            AssistantsCourses ass = new AssistantsCourses
            {
                AssistantId = AssistantId,
                CourseId    = CourseId,
                ClassType   = ClassType
            };

            _context.AssistantsCourses.Add(ass);
            _context.SaveChanges();
        }
        public void SetAsstant(int groupId, int assistantId)
        {
            var group = _context.Groups.First(a => a.GroupId == groupId);

            group.AssistantId = assistantId;

            // ako asistent nije bio zAduzen za kurs dodati ga

            int?CourseId = _context.Groups.Where(a => a.GroupId == groupId).Select(a => a.Division.CourseId).First();

            if (CourseId != null && !_context.AssistantsCourses.Any(a => a.AssistantId == assistantId && a.CourseId == CourseId.Value))
            {
                AssistantsCourses asscour = new AssistantsCourses
                {
                    AssistantId = assistantId,
                    CourseId    = CourseId.Value
                };
                _context.AssistantsCourses.Add(asscour);
            }

            _context.SaveChanges();
        }