title: Ruby: Rails: Which version of a gem is used?
body: <p>I have a Rails 3 application which has the following line in the Gemfile.</p>
  
  <pre><code>gem 'sqlite3', '1.3.6'
  </code></pre>
  
  <p>However, if I list my local gems I get:</p>
  
  <pre><code>&gt; gem list sqlite3 --local
  
  *** LOCAL GEMS ***
  
  sqlite3 (1.3.6, 1.3.4)
  </code></pre>
  
  <p>When my Rails apps does a </p>
  
  <pre><code>require 'sqlite3'
  </code></pre>
  
  <p>which version of the gem is selected? Is it that the first gem in the list is selected? Is there a way to tell the Ruby runtime to use version 1.3.4 even if version 1.3.6 is installed, and mandated by the Gemfile?</p>