title: Facebook App: localhost no longer works as app domain
body: <p>I've been writing a game for Facebook using Rails and jQuery.  Since I started using the Facebook Javascript SDK, using localhost as an app domain seemed to work just fine.  I was able to test my game both locally and on Heroku.</p>
  
  <p>In the past day, it seems that Facebook has made a big update to their developer UI.  Now if I add localhost as an app domain, it gives me the following error:</p>
  
  <blockquote>
    <p>This must be derived from Canvas URL, Secure Canvas URL, Site URL, Mobile Site URL, Page Tab URL or Secure Page Tab URL. Check and correct the following domains: localhost</p>
  </blockquote>
  
  <p>My game also now doesn't work locally and I get an error when the Javascript SDK logs in the user:</p>
  
  <blockquote>
    <p>API Error Code: 191 API Error Description: The specified URL is not
    owned by the application Error Message: Invalid redirect_uri: Given
    URL is not allowed by the Application configuration.</p>
  </blockquote>
  
  <p>This doesn't happen when I deploy my game, since herokuapp.com is considered a valid app domain.</p>
  
  <p>How am I supposed to develop and test my game if I can no longer use localhost or 127.0.0.1?</p>