title: How to upgrade to rails 3.2.11
body: <p>I upgraded via command</p>
  
  <pre><code>gem install rails
  </code></pre>
  
  <p>and it shows 1 gem <strong>rails 3.2.11 is installed successfully</strong>. But when I type <code>rails -v</code>, the version is still 3.2.9.</p>
  
  <p>Could anyone show me how to upgrade rails ? Thanks</p>