<td>
{!!link_to_route('events.edit', $title = 'Editar', $parameters = $event->id, $attributes = ['class'=>'btn btn-primary edit-event','onclick'=>'hola();'])!!}
</td>

public function edit($id)
{
    $categories = Category::lists('name_cat', 'id');
    $modalitys = Event::first()->modalitys;
    $discounts = $this->event->discounts;

    return view('event.edit',['events'=>$this->event,'categories'=>$categories, 'modalitys'=>$modalitys]);
}