title: Heroku starts Thin but returns error from weBrick - Devise User Create Failure
body: <p>When a new user registration is attempted I receive a server status code of 500 and no error is logged in Heroku. Here is the received response header:</p>
  
  <pre><code>Connection  keep-alive
  Content-Length  728
  Content-Type    text/html; charset=utf-8
  Date    Mon, 15 Apr 2013 16:43:30 GMT
  Server  WEBrick/1.3.1 (Ruby/1.9.2/2011-07-09)
  X-Runtime   0.390617
  </code></pre>
  
  <p>There is a Procfile that specifies thin and Heroku starts up fine:</p>
  
  <p>Procfile</p>
  
  <pre><code>web: bundle exec thin start -p $PORT
  worker:  bundle exec rake jobs:work
  </code></pre>
  
  <p>Also in my gemfile I specify ruby '1.9.3'</p>
  
  <p>Start up Log</p>
  
  <pre><code>2013-04-15T16:37:49.739237+00:00 heroku[web.1]: Starting process with command `bundle exec thin start -p 39185`
  (... Removed 3 warning - DEPRECATION WARNING: You have Rails 2.3-style plugins in vendor/plugins!)
  2013-04-15T16:37:55.104773+00:00 app[web.1]: &gt;&gt; Using rack adapter
  2013-04-15T16:37:55.104773+00:00 app[web.1]: Connecting to database specified by DATABASE_URL
  2013-04-15T16:37:57.202991+00:00 app[web.1]: &gt;&gt; Thin web server (v1.5.1 codename Straight Razor)
  2013-04-15T16:37:57.202991+00:00 app[web.1]: &gt;&gt; Maximum connections set to 1024
  2013-04-15T16:37:57.202991+00:00 app[web.1]: &gt;&gt; Listening on 0.0.0.0:39185, CTRL+C to stop
  2013-04-15T16:37:57.931278+00:00 heroku[web.1]: State changed from starting to up
  </code></pre>
  
  <p>It's not just devise that is failing. Any call to any page that is not static fails. Also the response header for any static page has Server:WEBrick/1.3.1 (Ruby/1.9.2/2011-07-09). </p>
  
  <p>What additional configuration items am I missing or should I validate.</p>