public async Task<string> SaveAllChangesAsync(bool invalidateCacheDependencies = true, Guid? auditUserId = null)
        {
            try
            {
                if (auditUserId.HasValue)
                    AuditFields(auditUserId.Value);
                await SaveChangesAsync();
                if (!invalidateCacheDependencies) return string.Empty;
                var changedEntityNames = GetChangedEntityNames();
                new EFCacheServiceProvider().InvalidateCacheDependencies(changedEntityNames);
            }
            catch (DbUpdateConcurrencyException ex)
            {
                Elmah.ErrorSignal.FromCurrentContext().Raise(ex);
                return ConcurrencyMessage;
            }
            return string.Empty;
        }

 public class NewsItemConfig : EntityTypeConfiguration<NewsItem>
    {
        public NewsItemConfig()
        {
            HasMany(a => a.Tags).WithMany().Map(m =>
            {
                m.MapLeftKey("TagId");
                m.MapRightKey("NewsItemId");
                m.ToTable("NewsItemTag");
            });
      
        }
    }

var news= from p in ctx.NewsItems
                 from t in p.Tags
                 where t.Name == "Tag1"
                 select p;