title: How does after_save work when saving an object
body: <p>If I do the following:</p>
  
  <pre><code>@user.name = "John"    
  @user.url = "www.john.com"
  @user.save
  </code></pre>
  
  <p>If I use <code>after_save</code></p>
  
  <pre><code>@user.url = "www.johnseena.com"
  @user.save
  </code></pre>
  
  <p>What will happen when I do this?</p>
  
  <p>I believe it should save the value because of the 'after_save' callback. </p>