title: ASP.NET identity use email instead of user name
body: <p>How can I use email instead of user name in the new ASP.NET identity system?</p>
  
  <p>I tried to change the <code>RegisterViewModel</code> class:</p>
  
  <pre><code>[Display(Name = "Email address")]
  [Required(ErrorMessage = "The email address is required")]
  [EmailAddress(ErrorMessage = "Invalid Email Address")]
  public string UserName { get; set; }
  </code></pre>
  
  <p>but when I enter an mail adress I am getting the error:</p>
  
  <pre><code>User name fsdfsd@fsdfsd.de is invalid, can only contain letters or digits.
  </code></pre>