Here's a CD bike I built with an additional Q128 hub-motor in the front wheel. The controller is under the frame in front of the crank-motor. The Bosch battery probably doesn't give enough power to run two motors, so you'd need an additional battery mounted somewhere.
This bike has three motors running off two batteries and three controllers. It was like being shot from a gun when you opened up the throttle up a 15% hill (5.5kW):