title: Date of news is updated with text of news is corrected
body: <p>There is admin panel where admin adds, edits or deletes news. Each news consist of "Title", "Body" and "Created". It's shown for site users.</p>
  
  <p>However, there is a problem with date ("Created"). For example, news is created on 25 January, but admin edited it on 27 January. Аfter this it's shown as 27 January instead of 25 January - that isn't correct because it was created two days before.</p>
  
  <p>I understand it's because when admin updates news and DateTime.Now function refreshes Created value. How can I remember time of creation "Post" in "Created"?</p>
  
  <p>Post.cs</p>
  
  <pre><code>namespace Blog.Models
  {
      public class Post
      {
          public int Id { get; set; }
          public string Title { get; set; } = "";
          public string Body { get; set; } = "";
          public DateTime Created { get; set; } = DateTime.Now;
      }
  }
  </code></pre>
  
  <p>PanelController.cs</p>
  
  <pre><code>[HttpGet]
  public IActionResult Edit(int? id)
  {
      if (id == null)
      {
          return View(new PostViewModel());
      }
      else
      {
          var post = _repo.GetPost((int)id);
          return View(new PostViewModel
          {
              Id = post.Id,
              Title = post.Title,
              Body = post.Body
          });
      }
  }
  
  [HttpPost]
  public async Task&lt;IActionResult&gt; Edit(PostViewModel vm)
  {
      var post = new Post
      {
          Id = vm.Id,
          Title = vm.Title,
          Body = vm.Body
      };
      if (post.Id &gt; 0)
          _repo.UpdatePost(post);
      else
          _repo.AddPost(post);
      if (await _repo.SaveChangesAsync())
          return RedirectToAction("Index");
      else
          return View(post);
  }
  </code></pre>