title: Can't check in .mdf/.ldf in App_Data into TFS
body: <p>I am working with ASP.NET C# MVC 5.</p>
  
  <p>.mdf/.ldf files in App_Data do not appear on Pending Changes in team explorer. Therefore I can't check them into TFS(visual studio online). I've tried recreating the project a few times and none worked. What might be the cause for this?</p>