laravel-learn-bbs/app/Providers/AppServiceProvider.php

<?php

namespace App\Providers;

use App\Models\Reply;
use App\Models\Topic;
use App\Observers\ReplyObserver;
use App\Observers\TopicObserver;
use Carbon\Carbon;
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Carbon::setLocale('zh');
        Topic::observe(new TopicObserver());
        Reply::observe(new ReplyObserver());

    }

    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        if ($this->app->environment() !== 'production') {
            $this->app->register(\Barryvdh\LaravelIdeHelper\IdeHelperServiceProvider::class);
        }
    }
}