Laravel Passing Parameters in URL

I have a webhook in a website, so that when a certain action is performed, one of my functions in my Laravel app is executed with the PUT method. The webhook has the following url to execute app.myapp.com/sync/documents/gt?salesID=12345.

How do I receive this parameter in Laravel?

This is my route:

Route::put('/sync/vendus/documents/gt', 'SyncController@postVendusGT');

And then in my method I have:

public function postVendusGT($request){
    dd($request->salesID);
}

But I'm getting the following error:

Missing argument 1 for App\Http\Controllers\SyncController::postVendusGT()

Am I doing this right?

via Adam Silva