public function __construct()
 {
     Answer::truncate();
     Question::truncate();
     $this->users = User::all(['id'])->lists('id');
     $this->categories = Category::all(['id'])->lists('id');
 }
 /**
  * Run the database seeds.
  *
  * @return void
  */
 public function run()
 {
     Category::truncate();
     factory(Category::class, 20)->create();
 }