title: how retrieve google access token with asp 5 core
body: <p>Hi I've not found the way to retrieve access token..</p>
  
  <p>here's my code: (file startup.cs)
  I've use mvc template from asp 5 (Vs 2015)</p>
  
  <pre><code>    services.Configure&lt;GoogleAuthenticationOptions&gt;(options =&gt;
      {
          options.ClientId = Configuration["Authentication:Google:ClientId"];
          options.ClientSecret = Configuration["Authentication:Google:ClientSecret"];
          options.AccessType= Configuration["Authentication:Google:AccessType"];
  
          options.Scope.Add(@"https://www.googleapis.com/auth/userinfo.email");
  
          //options.CallbackPath
      });
  </code></pre>
  
  <p>logging works fine, I can retrieve name and other useful information but not token or refresh token...</p>
  
  <p>attention.. <code>GoogleAuthenticationOptions</code>is : Microsoft.AspNet.Authentication.Google.GoogleAuthenticationOptions which is compatible with asp core, owin version is not.</p>
  
  <p>thanks</p>