title: Twitter sign in crashes with TWTRInvalidInitializationException
body: <p>My app crashes when i try to login with twitter, with an error message</p>
  
  <p><strong>Attempt made to Log in or Like a Tweet without a valid Twitter Kit URL Scheme set up in the app settings. Please see <a href="https://dev.twitter.com/twitterkit/ios/installation" rel="nofollow noreferrer">https://dev.twitter.com/twitterkit/ios/installation</a> for more info.</strong></p>
  
  <p>I have applied twitter login using fabric.But after converting my code from swift 2.3 to swift 3, it started crashing.I have updated my pods too and reapplied the steps for sign in again without fabric, as fabric is not showing the twitter option now. But still the crash remains.</p>