title: AuthenticationManager references missing
body: <p>Following up <a href="https://stackoverflow.com/questions/21564260/registration-method-with-identity-on-an-empty-project/21564504#21564504">this</a> question, there are missing the references for the methods <code>SignOut()</code> and <code>SignIn()</code>:</p>
  
  <pre><code>private async Task SignInAsync(User user, bool isPersistent)
  {
      AuthenticationManager.SignOut(DefaultAuthenticationTypes.ExternalCookie);
      var identity = await UserManager.CreateIdentityAsync(user, DefaultAuthenticationTypes.ApplicationCookie);
      AuthenticationManager.SignIn(new AuthenticationProperties() { IsPersistent = isPersistent }, identity);
  }
  </code></pre>
  
  <p>Do someone knows how to solve it?</p>