title: Bundler - cannot load 2 different versions of the exact same gem?
body: <p>I've watched this presentation on <a href="https://www.youtube.com/watch?v=4DqzaqeeMgY" rel="nofollow noreferrer">how Bundler works</a> and one of the reasons Bundler was invented was to solve 'activation errors', for eg:</p>
  
  <pre><code>LoadError: can't activate rack (~&gt; 1.0.0, runtime) for ['actonpack-2.3.5'], already activated rack-1.1.0 for ['thin-1.2.7']
  </code></pre>
  
  <p>Does this basically means that you cannot run 2 different versions of the exact same gem at a same time, in a single Ruby process? </p>