title: Load an xml file in ruby, and add a node inside a given node
body: <p>I have an xml that looks like:</p>
  
  <pre><code>&lt;Server&gt;
  ...
  ..
  &lt;Host ......&gt;
  &lt;/Host&gt;
  
  
  &lt;/Server&gt;
  </code></pre>
  
  <p>Now inside the  element, I want to insert a child node:</p>
  
  <pre><code>&lt;Site name="Hello" path="/some/path/here" /&gt;
  </code></pre>
  
  <p>How would I do this in Ruby? </p>