Command "serve" is not defined (Lumen-Laravel)

So, i try to install the lumen restful api. Based on tutorial, i have to "serve" on php artisan. The command be like:

php artisan serve sample_api sample_api/public

then it shows:

Command "serve" not defined.

Some say that serve command has been deleted in laravel 5 (which i use it). if so, what command should i use? or maybe find another tutorial?

Ps: Im a newbie :)

Thanks a lot!