title: Ruby gem loaded but still gives "uninitialized constant"
body: <p>I don't understand this output:</p>
  
  <pre><code>$ rails c
  Loading development environment (Rails 3.2.14)
  1.9.3p392 :001&gt; require 'rubygems'
   =&gt; false 
  1.9.3p392 :002 &gt; require 'mongo'
   =&gt; false 
  1.9.3p392 :003 &gt; include Mongo
   =&gt; Object 
  1.9.3p392 :004 &gt; Mongo::VERSION
   =&gt; "1.6.0" 
  1.9.3p392 :005 &gt; c = MongoClient.new
  NameError: uninitialized constant MongoClient
      from (irb):5
  </code></pre>
  
  <p>Clearly bundler is running correctly and loading the MongoDB driver gem "mongo" (version 1.6, which should be fine).</p>
  
  <p>Yet when I try to reference MongoClient according to the docs, I get "uninitialized constant." The same happens if I try to reference it as Mongo::MongoClient.new</p>
  
  <p>What am I missing here?</p>