title: How can we use opencart events?
body: <p>I have searched a lot about opencart triggers but didn't find a proper example. In opencart 2.0 there are triggers on which developer can hook function and perform something just like wordpress action and filters i guess. For example in</p>
  
  <pre><code>catalog/model/checkout/order.php
  </code></pre>
  
  <p>there is a trigger <code>$this-&gt;event-&gt;trigger('post.order.history.add', $order_id)</code></p>
  
  <p>Can someone help me to hook my function on the above trigger?</p>