title: Heroku deploy fails after upgrading to bootstrap 2.0.1 via twitter-bootstrap-rails gem
body: <p>UPDATE:</p>
  
  <p>this error is shown during <code>git push heroku master</code> :</p>
  
  <pre><code>-----&gt; Preparing app for Rails asset pipeline
         Running: rake assets:precompile
         rake aborted!
         couldn't find file 'twitter/bootstrap'
         (in /tmp/build_2pmsvze33th3e/app/assets/javascripts/application.js:9)
  
         Tasks: TOP =&gt; assets:precompile:primary
         (See full trace by running task with --trace)
         Precompiling assets failed, enabling runtime asset compilation
         Injecting rails31_enable_runtime_asset_compilation
         Please see this article for troubleshooting help:
         http://devcenter.heroku.com/articles/rails31_heroku_cedar#troubleshooting
  </code></pre>
  
  <p>I upgraded Bootstrap 2 layout to 2.0.1 by following this <a href="https://github.com/seyhunak/twitter-bootstrap-rails/wiki/Upgrading-Guide" rel="nofollow">guide</a>.  After that I get this error deploing to Heroku :</p>
  
  <pre><code>2012-02-23T23:12:09+00:00 app[web.1]: ActionView::Template::Error ('twitter/bootstrap.less' wasn't found.
  2012-02-23T23:12:09+00:00 app[web.1]: 
  2012-02-23T23:12:09+00:00 app[web.1]:   (in /app/app/assets/stylesheets/bootstrap.css.less)):
  2012-02-23T23:12:09+00:00 app[web.1]:     7:     /%title gitwatcher.com
  2012-02-23T23:12:09+00:00 app[web.1]:     8:     = csrf_meta_tags
  2012-02-23T23:12:09+00:00 app[web.1]:     9:     = stylesheet_link_tag "vendor",       :media =&gt; "screen"
  2012-02-23T23:12:09+00:00 app[web.1]:     10:     = stylesheet_link_tag "application",  :rel =&gt; "stylesheet"
  2012-02-23T23:12:09+00:00 app[web.1]:     11:     = stylesheet_link_tag "http://jqueryui.com/repository/tags/latest/themes/base/jquery.ui.all.css", :media =&gt; "screen, projection"
  2012-02-23T23:12:09+00:00 app[web.1]:     12:     / 
  2012-02-23T23:12:09+00:00 app[web.1]:     13:     :css
  2012-02-23T23:12:09+00:00 app[web.1]:   app/views/layouts/application.html.haml:10:in `_app_views_layouts_application_html_haml___2608554683581233975_52490540'
  2012-02-23T23:12:09+00:00 app[web.1]: 
  2012-02-23T23:12:09+00:00 app[web.1]: 
  2012-02-23T23:12:09+00:00 app[web.1]: cache: [GET /] miss
  2012-02-23T23:12:09+00:00 app[web.1]:   Processing by HomeController#index as HTML
  2012-02-23T23:12:09+00:00 app[web.1]: Rendered shared/_watch-list-tab.html.haml (4.5ms)
  2012-02-23T23:12:09+00:00 app[web.1]: Rendered shared/_watch-list-table.html.haml (30.2ms)
  2012-02-23T23:12:09+00:00 app[web.1]: Rendered home/index.html.haml within layouts/application (101.7ms)
  2012-02-23T23:12:09+00:00 app[web.1]: Compiled vendor.css  (3ms)  (pid 1)
  2012-02-23T23:12:09+00:00 app[web.1]: Compiled css3-github-buttons/gh-buttons.css  (0ms)  (pid 1)
  2012-02-23T23:12:09+00:00 app[web.1]: Compiled jquery_carousel/carousel.css  (0ms)  (pid 1)
  2012-02-23T23:12:09+00:00 app[web.1]: Compiled application.css  (2ms)  (pid 1)
  2012-02-23T23:12:09+00:00 app[web.1]: Completed 500 Internal Server Error in 858ms
  </code></pre>
  
  <p>Previously I got an existing Rails 3.1.3 app already working with Bootstrap 2 layout on Heroku Cedar. </p>
  
  <p>Any idea ?</p>