title: call a function after a column is changed
body: <p>I would like to know when a column in my table is changed.</p>
  
  <p>for example, if an user changed <code>fist-name</code> column , I would like to find out it (to call my custom function).</p>
  
  <p>is there any <code>function/library/plugin</code> in laravel to help me ?</p>