title: select all html elements based on rel value
body: <p>I have some html elements in my code like this</p>
  
  <pre><code>&lt;div rel="test1"&gt;item1&lt;/div&gt;
  &lt;div rel="test1"&gt;item2&lt;/div&gt;
  &lt;div rel="test1"&gt;item3&lt;/div&gt;
  &lt;div rel="test2"&gt;item4&lt;/div&gt;
  &lt;div rel="test2"&gt;item5&lt;/div&gt;
  </code></pre>
  
  <p>and I need a way to select all the divs that use <code>rel="test1"</code> and add a class to them
  how can I do this with <code>jQuery</code>?</p>