title: no such file to load -- sinatra/session (LoadError)
body: <p>I can't run the ruby web application, and I get this message error:</p>
  
  <pre><code>rackup webapp/config.ru --debug
  nil
  Exception `LoadError' at /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31 - no such file to load -- sinatra/base
  Exception `LoadError' at /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31 - no such file to load -- sinatra/session
  Exception `LoadError' at /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:38 - no such file to load -- sinatra/session
  Exception `LoadError' at /usr/lib/ruby/gems/1.8/gems/rack-1.5.2/lib/rack/builder.rb:49 - no such file to load -- sinatra/session
  /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- sinatra/session (LoadError)
          from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
          from /usr/local/deployer/webapp/config.ru:3
          from /usr/lib/ruby/gems/1.8/gems/rack-1.5.2/lib/rack/builder.rb:55:in `instance_eval'
          from /usr/lib/ruby/gems/1.8/gems/rack-1.5.2/lib/rack/builder.rb:55:in `initialize'
          from /usr/local/deployer/webapp/config.ru:0:in `new'
          from /usr/local/deployer/webapp/config.ru:0
  </code></pre>
  
  <p>It seems like it cannot find where sinatra is.
  My config.ru is:</p>
  
  <pre><code>require 'rubygems'
  require 'sinatra/base'
  require 'sinatra/session'
  require './lib/miscsystem'
  require './lib/deployer'
  
  run Deployer
  </code></pre>
  
  <ul>
  <li>I did a : gem install sinatra</li>
  </ul>
  
  <p>Here is the output of #gem env</p>
  
  <pre><code># gem env
  RubyGems Environment:
    - RUBYGEMS VERSION: 1.3.7
    - RUBY VERSION: 1.8.7 (2011-06-30 patchlevel 352) [x86_64-linux]
    - INSTALLATION DIRECTORY: /usr/lib/ruby/gems/1.8
    - RUBY EXECUTABLE: /usr/bin/ruby
    - EXECUTABLE DIRECTORY: /usr/bin
    - RUBYGEMS PLATFORMS:
      - ruby
      - x86_64-linux
    - GEM PATHS:
       - /usr/lib/ruby/gems/1.8
       - /root/.gem/ruby/1.8
    - GEM CONFIGURATION:
       - :update_sources =&gt; true
       - :verbose =&gt; true
       - :benchmark =&gt; false
       - :backtrace =&gt; false
       - :bulk_threshold =&gt; 1000
       - :sources =&gt; ["http://rubygems.org/"]
    - REMOTE SOURCES:
       - http://rubygems.org/
  </code></pre>
  
  <p>Any help?</p>