title: Bundler fails with Rbenv
body: <p>I have inherited a rails 2.3.2 application and got it to work using ruby 1.8.7 under rbenv including some old versions of other gems and software.</p>
  
  <p>Now I have generated a Gemfile and try to verify it by runing any bundle comand on it, e.g. bundle check, install, etc. but any of these operations fail. I installed the rbenv bundler plugin which makes it look a little lesss severe but  I still can't figure it out.</p>
  
  <pre><code>$ bundle -V
  /usr/local/lib/site_ruby/1.9.1/rubygems.rb:846: Use RbConfig instead of obsolete and deprecated Config.
  /usr/lib/ruby/vendor_ruby/bundler/rubygems_integration.rb:310:in `&lt;module:Bundler&gt;': uninitialized constant Gem::VERSION (NameError)
      from /usr/lib/ruby/vendor_ruby/bundler/rubygems_integration.rb:1:in `&lt;top (required)&gt;'
      from /usr/lib/ruby/vendor_ruby/bundler.rb:12:in `require'
      from /usr/lib/ruby/vendor_ruby/bundler.rb:12:in `&lt;top (required)&gt;'
      from /usr/bin/bundle:4:in `require'
      from /usr/bin/bundle:4:in `&lt;main&gt;'
  </code></pre>
  
  <p>My bundler installation:</p>
  
  <pre><code>$ which bundle
  /usr/bin/bundle
  </code></pre>
  
  <p>Ruby:</p>
  
  <pre><code>$ ruby -v
  ruby 1.8.7 (2012-02-08 patchlevel 358) [x86_64-linux]
  </code></pre>
  
  <p>Rbenv gives me problems too now: </p>
  
  <pre><code>$ rbenv alternatives 
  Skipping 1.8.7-debian, it already exists
  /usr/local/lib/site_ruby/1.9.1/rubygems.rb:846: Use RbConfig instead of obsolete and deprecated Config.
  Skipping 1.9.3-debian, it already exists
  </code></pre>
  
  <p>Isn't there supposed to be a shim for bundler? It seems that bundler is called directly. </p>
  
  <p>I am lost. If anyone could help me with this I would be glad.</p>
  
  <p>p.s.: I also just discovered this:</p>
  
  <pre><code>$ rbenv rehash 
  /usr/local/lib/site_ruby/1.9.1/rubygems.rb:846: Use RbConfig instead of obsolete and deprecated Config.
  /usr/lib/ruby/vendor_ruby/bundler/rubygems_integration.rb:310:in `&lt;module:Bundler&gt;': uninitialized constant Gem::VERSION (NameError)
      from /usr/lib/ruby/vendor_ruby/bundler/rubygems_integration.rb:1:in `&lt;top (required)&gt;'
      from /usr/lib/ruby/vendor_ruby/bundler.rb:12:in `require'
      from /usr/lib/ruby/vendor_ruby/bundler.rb:12:in `&lt;top (required)&gt;'
      from /home/bernhard/.rbenv/plugins/bundler/etc/rbenv.d/bundler/rehash.rb:361:in `require'
      from /home/bernhard/.rbenv/plugins/bundler/etc/rbenv.d/bundler/rehash.rb:361:in `require_and_patch_bundler'
      from /home/bernhard/.rbenv/plugins/bundler/etc/rbenv.d/bundler/rehash.rb:427:in `&lt;main&gt;'
  cat: /home/bernhard/.rbenv/plugins/bundler/share/rbenv/bundler/manifest.txt: No such file or directory
  </code></pre>