So you want real stoppers on your Ruckus? The parts needed aren't that many. It's a basic mod that really is worth the time and money.
Master Cylinder
Brake Hose
Banjo Bolts and Washers X2
Disc Brake Type Fork Set
Brake Caliper
Brake Rotor
Caliper Bolts
Rotor Bolts
Disc Brake Type Front Wheel