title: rake aborted! couldn't find file twitter/bootstrap
body: <p>i'm following the Hartl tutorial about ROR 3.2, i build a simple app that works fine locally but when i try to deploy it to heroku wit $git push heroku master , the rake assets:precompile fails because  "couldn't find file twitter/bootstrap". (error raised by application.js) 
  I've already google the problem but none of these answers work for me:
  <a href="https://stackoverflow.com/questions/9423067/heroku-deploy-fails-after-upgrading-to-bootstrap-2-0-1-via-twitter-bootstrap-rai">Heroku deploy fails after upgrading to bootstrap 2.0.1 via twitter-bootstrap-rails gem</a></p>
  
  <p><a href="https://stackoverflow.com/questions/9047478/rails-app-with-twitter-bootstrap-works-in-development-but-not-in-production">Couldn&#39;t find file &#39;twitter/bootstrap&#39; in Production</a></p>
  
  <p>can anyone help me to figure out the problem? 
  If i have to attach some files, or if you needother informations please tell me.
  Thank you</p>
  
  <p>here the Gemfile</p>
  
  <pre><code>gem 'rails', '3.2.6'
  
  group :development do
  gem 'sqlite3'
  gem 'annotate', '~&gt; 2.4.1.beta'
  end
  
  group :production do
    gem 'pg'
  end
  
  group :assets do
    gem 'sass-rails',   '~&gt; 3.2.3'
    gem 'coffee-rails', '~&gt; 3.2.1'
    gem 'twitter-bootstrap-rails', '~&gt; 2.0.1.0'
    gem 'bootstrap-sass', '~&gt; 2.0.3'
    gem 'uglifier', '&gt;= 1.0.3'
  end
  
  gem 'jquery-rails'
  gem 'bcrypt-ruby', '3.0.1'
  </code></pre>