title: Redirecting user back to originally desired URL after login
body: <p>Example:  </p>
  
  <ol>
  <li>User is not logged in</li>
  <li>User has items in their shopping cart</li>
  <li>User goes to /checkout</li>
  <li>User is redirected to the /login page</li>
  <li>User logs in successfully and should be redirected back to the /checkout page</li>
  </ol>
  
  <p>How does the login action know to redirect the user to checkout in this case? I want this to work in many different situations not just /checkout.</p>