private async Task <Tuple <Tags, IPagedList <PostViewModel> > > GetPostsByTag(string tagName, int page)
        {
            var query = _postManager.GetQueryable();

            var tag = await _tagManager.FindByNameAsync(tagName);

            if (tag != null)
            {
                query = query.Where(t => t.Tags.Any(c => c.TagsId == tag.Id));
            }

            var result = await GetPosts(query, page);

            return(new Tuple <Tags, IPagedList <PostViewModel> >(tag, result));
        }