title: Correct way to auto load nested directory. Why the trailing forward slash?
body: <p>This works (with the trailing forward slash):</p>
  
  <pre><code>config.autoload_paths += Dir[Rails.root.join("lib", "**/")]
  </code></pre>
  
  <p>This doesn't work (without the slash):</p>
  
  <pre><code>config.autoload_paths += Dir[Rails.root.join("lib", "**")]
  </code></pre>
  
  <p>Why?</p>