title: Spotify Callback URI error
body: <p>I'm working on my first app using ruby on rails and have run into a few problems when I deploy to Heroku. When I sign into Spotify on my app I get an error saying:</p>
  
  <p><code>INVALID_CLIENT: Invalid redirect URI</code></p>
  
  <p>in my console the error reads: </p>
  
  <p><code>Failed to load resource: the server responded with a status of 400 (Bad Request)</code></p>
  
  <p>At first I thought it was an issue with my Client ID and Secret, because I ran into a similar error locally. So I regenerated new ones and I still have the same issue. </p>
  
  <p>Then I noticed my callback URI didn't include a 's' in the callback url, so I added it and changed the callback on my Spotify App page, but I still receive the same error. </p>
  
  <p>Although I changed the callback url in Spotify's app page, when I am in my app and I try to log in the url still doesn't contain an 's'. </p>
  
  <p>Am I missing something or is something happening on Spotify's end? 
  (I don't have this issue when I run this app locally)</p>