title: MVC 5 Identity and error message
body: <p>I am using the Identity 2.0 and I want to know how to customize the error message when I try to register a user that already been registered.
  The follow message is what I receving:</p>
  
  <ul>
  <li>Name xxxxx is already taken.</li>
  </ul>
  
  <p>Tks.</p>