public function run()
{
$faker = Faker::create();
$users = User::lists('id')->all();
$topics = Topic::lists('id')->all();
foreach (range(1, 500) as $index) {
factory(App\Reply::class)->create(['user_id' => $faker->randomElement($users), 'topic_id' => $faker->randomElement($topics)]);
}
}
