title: Difference between after_create, after_save and after_commit in rails callbacks
body: <p>The difference between <code>after_create</code>, <code>after_save</code> and <code>after_commit</code> in Rails is that: </p>
  
  <ul>
  <li><code>after_save</code> is invoked when an object is created and updated</li>
  <li><code>after_commit</code> is called on create, update and destroy. </li>
  <li><code>after_create</code> is only called when creating an object</li>
  </ul>
  
  <p>Is this the only difference among those, or are there any other major differences?</p>