title: send email on form submit only when a field has changed
body: <p>I have a form to edit a job, a job has a status column which can be 1, 2 or 3</p>
  
  <pre><code>&lt;?php echo $this-&gt;Form-&gt;input('status', array('label' =&gt; '', 'options' =&gt; $status)); ?&gt;
  </code></pre>
  
  <p>When i submit the form i want to check if the value of status is equal to 3, if it is then i want to send an email. BUT i dont want to send the email if the value was 3 already.</p>
  
  <p>Is there an easy way in cakephp to check the previous value to the new value etc?</p>
  
  <p>Thanks.</p>