title: Laravel Eloquent update just if changes have been made
body: <p>Is there any way to update a record in Laravel using eloquent models just if a change has been made to that record? I don't want any user requesting the database for no good reason over and over, just hitting the button to save changes. I have a <code>javascript</code> function that enables and disables the save button according with whether something has changed in the page, but I would like to know if it's possible to make sure to do this kind of feature on the server side too. I know I can accomplish it by myself (meaning: without appealing to an internal functionality of the framework) just by checking if the record has change, but before doing it that way, I would like to know if Laravel eloquent model already takes care of that, so I don't need to re-invent the wheel.</p>
  
  <p>This is the way I use to update a record:</p>
  
  <pre><code>$product = Product::find($data["id"]);
  $product-&gt;title = $data["title"];
  $product-&gt;description = $data["description"];
  $product-&gt;price = $data["price"];
  //etc (string values were previously sanitized for xss attacks)
  $product-&gt;save();
  </code></pre>