title: Unable to load the EventMachine C extension; To use the pure-ruby reactor
body: <p>i got trouble, in a rails project（redmine2.3), rails version is 3.2</p>
  
  <p>start the project</p>
  
  <pre><code>bundle exec thin start -p 8080 -e production -s 5 -d
  </code></pre>
  
  <p>error info</p>
  
  <pre><code>(eval):9: warning: already initialized constant Bundler::Dsl::RAILS_VERSION_IS_3
  (eval):9: warning: previous definition of RAILS_VERSION_IS_3 was here
  (eval):9: warning: already initialized constant Bundler::Dsl::RAILS_VERSION_IS_3
  (eval):9: warning: previous definition of RAILS_VERSION_IS_3 was here
  Unable to load the EventMachine C extension; To use the pure-ruby reactor, require 'em/pure_ruby'
  /var/wtn/vendor/cache/ruby/2.0.0/gems/eventmachine-1.0.3/lib/eventmachine.rb:8:in `require': libruby.so.2.0: cannot open shared object file: No such file or directory - /var/wtn/vendor/cache/ruby/2.0.0/gems/eventmachine-1.0.3/lib/rubyeventmachine.so (LoadError)
      from /var/wtn/vendor/cache/ruby/2.0.0/gems/eventmachine-1.0.3/lib/eventmachine.rb:8:in `&lt;top (required)&gt;'
      from /var/wtn/vendor/cache/ruby/2.0.0/gems/thin-1.6.2/lib/thin.rb:7:in `require'
      from /var/wtn/vendor/cache/ruby/2.0.0/gems/thin-1.6.2/lib/thin.rb:7:in `&lt;top (required)&gt;'
      from /var/wtn/vendor/cache/ruby/2.0.0/gems/thin-1.6.2/bin/thin:5:in `require'
      from /var/wtn/vendor/cache/ruby/2.0.0/gems/thin-1.6.2/bin/thin:5:in `&lt;top (required)&gt;'
      from /var/wtn/vendor/cache/ruby/2.0.0/bin/thin:23:in `load'
      from /var/wtn/vendor/cache/ruby/2.0.0/bin/thin:23:in `&lt;main&gt;'
  </code></pre>
  
  <p>the same error happens when running <code>rails -v</code></p>
  
  <pre><code>rails -v
  (eval):9: warning: already initialized constant Bundler::Dsl::RAILS_VERSION_IS_3
  (eval):9: warning: previous definition of RAILS_VERSION_IS_3 was here
  </code></pre>
  
  <p>running <code>bundle exec .....</code> in the project produces the same error</p>
  
  <p>the problem has solved, see my comment in the third floor , there are the answer</p>