FluxBB\Core\FilesystemServiceProvider::register PHP Method

    public function register()
    {
        $this->app->singleton('files', function () {
            return new Filesystem();
        });
        $this->app->singleton('filesystem', function () {
            $flysystem = new Flysystem(new LocalAdapter($this->app->make('path')));
            return new FilesystemAdapter($flysystem);
        });
        $this->app->alias('filesystem', 'Illuminate\\Contracts\\Filesystem\\Filesystem');
    }