title: Ruby on Rails bundles downgrade
body: <p>I am working on ROR and incidentally I upgraded my bundles with <code>bundle update</code> command, I got message that bundles are up to date, but when am trying to start my rails server <code>rails s</code> it is throwing me an error:</p>
  
  <pre><code>/var/lib/gems/1.9.1/gems/devise-3.2.4/lib/devise/models.rb:88:in `const_get': uninitialized constant Devise::Models::TokenAuthenticatable (NameError)
  </code></pre>
  
  <p>Please tell me what I have to do to solve this. I have done lots of R&amp;D on this, but not get any answer. I installed rails with <code>sudo apt-get install rails</code> not RVM. I think there is an option to downgrade rails version with RVM.<br>
  please help.</p>