Add ability to define collection & item after resource name

[antonkomarev]

I've faced a situation where I'm creating fractal response in constructor and filling resources in methods:

public function __construct(Request $request)
{
    $this->response = fractal()
        ->withResourceName('users')
        ->transformWith(new UserTransformer)
        ->parseIncludes($request->input('include'));
}

public function index()
{
    // Some logic

    return $this->response->collection($users)->respond();
}

public function show($id)
{
    // Some logic

    return $this->response->item($user)->respond();
}

Without this change collection & item methods overwriting resourceName variable with null value and the only way to make it work - use data('collection', $users) method instead.

[freekmurze]

Thanks!