public IHttpActionResult CreateGroup(GroupViewModels create)
        {
            using (var transaction = db.Database.BeginTransaction())
            {
                try
                {
                    // add group
                    var group = new t_group()
                    {
                        GroupName   = create.GroupName,
                        GroupType   = create.GroupType,
                        Description = create.Description,
                        Members     = create.Members
                    };
                    db.t_group.Add(group);
                    db.SaveChanges();
                    // add members
                    int groupId = group.GroupId;
                    foreach (var item in create.TagList)
                    {
                        var member = new t_memeber
                        {
                            Name    = item,
                            Email   = item,
                            GroupId = groupId,
                            Status  = "1"
                        };
                        db.t_memeber.Add(member);
                    }
                    db.SaveChanges();
                    transaction.Commit();
                }
                catch (Exception)
                {
                    transaction.Rollback();
                    return(NotFound());
                }
            }

            return(Ok());
        }