public override void Add(Article entity)
 {
     entity.CreatedDate  = DateTime.Now;
     entity.ReadingCount = 1;
     entity.ReadTime     = ArticleHelper.CalculateReadTime(entity.Content);
     entity.IsPublished  = false;
     base.Add(entity);
 }
 public override void Update(Article entity)
 {
     entity.ReadTime = ArticleHelper.CalculateReadTime(entity.Content);
     base.Update(entity);
 }