[Andy Sheu]

You need to add the new OpMode to the list of OpModes in FtcOpModeRegister.java.

Add the following line inside the preexisting register method:
manager.register("K9TeleOp", K9TeleOp.class);
Replace K9TeleOp with whatever you want to name the OpMode and replace K9TeleOp.class with the class name.