I have some code that looks like this:

class User {
    public function addRoleById($role_id) {
       $this->roles()->attach($role_id);
   }   
}

// main() - does not work
$user = User::find(1);
$user->addRoleById(7);  // succeeds, change now visible in database.
echo "Roles now include ". $user->roles; // new role is missing

// alternate main() -- does work
$user = User::find(1);
$user->addRoleById(7);  // succeeds, change now visible in database.
$user = User::find(1) // reloads record I should already have and that has not changed?
echo "Roles now include ". $user->roles; // new role is present

To make this code work, I have to reload a database object immediately following an attach(), which I would not have intuitively expected. Am I doing something wrong in the first (non-working) case? Is there a more elegant workaround than reloading the object?