title: open xml file with nokogiri update node and save
body: <p>I'm trying to figure out how to open an xml file, search by an id, replace a value in the node and then resave the document.</p>
  
  <p>my xml</p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  &lt;data&gt;
      &lt;user id="1370018670618"&gt;
        &lt;email&gt;1@1.com&lt;/email&gt;
        &lt;sent&gt;false&lt;/sent&gt;
      &lt;/user&gt;
      &lt;user id="1370018701357"&gt;
        &lt;email&gt;2@2.com&lt;/email&gt;
        &lt;sent&gt;false&lt;/sent&gt;
      &lt;/user&gt;
      &lt;user id="1370018769724"&gt;
        &lt;email&gt;3@3.com&lt;/email&gt;
        &lt;sent&gt;false&lt;/sent&gt;
      &lt;/user&gt;
      &lt;user id="1370028546850"&gt;
        &lt;email&gt;4@4.com&lt;/email&gt;
        &lt;sent&gt;false&lt;/sent&gt;
      &lt;/user&gt;
      &lt;user id="1370028588345"&gt;
        &lt;email&gt;5@5.com&lt;/email&gt;
        &lt;sent&gt;false&lt;/sent&gt;
      &lt;/user&gt;
  &lt;/data&gt;
  </code></pre>
  
  <p>My code to open and find a node</p>
  
  <pre><code>xml_content = File.read("/home/mike/app/users.xml")
  doc = Nokogiri::XML(xml_content)
  node_update = doc.search("//user[@id='1370028588345'] //sent")
  node_update.inner_html ##returns value of "sent"
  </code></pre>
  
  <p>the part in this where I'm stuck is actually updating the node. <code>node_update.inner_html = "true"</code> returns a method error on <code>inner_html</code>. then after that saving the updated file.</p>