[5.5] Track model changes after persisting to database

[themsaid]

Currently:

$user->name = 'new name';

// This returns the name attribute with its new value
$user->getDirty();

$user->save();

// Now that the user is saved getDirty() will return an empty array
$user->getDirty();

What Changed:

$user->name = 'new name';

$user->save();

// getChanges() will return an array of the name attribute with its new value
$user->getChanges();

This allows for doing some useful checks after model is saved, for example if a Server was activated we want to send notification to customer.

$server->update(request()->all());

if($server->isChanged('active') && $server->active){
   Notification::send(....);
}