Class UsersTableSeeders does not exist [ReflectionException]

    <?php
use Illuminate\Database\Seeder;
use App\User;

class UsersTableSeeders extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
       User::create([
                'name'=>'prakash',
                'username'=>'prakash',
                'email'=>'rockpokhrel@gmail.com',
                'password'=> bycrypt('pokhrel'),
                'remember_token'=> str_random(10),
            ]);
    }
}

I don't understand why i receiving this error : [ReflectionException] Class UsersTableSeeders does not exist