public ManualDriveCommand() {
    // Use requires() here to declare subsystem dependencies
    drivetrain = Drivetrain.getInstance();
    requires(drivetrain);

    this.joystick = OI.getInstance().rightStick;
  }
 // Called once after isFinished returns true
 protected void end() {
   drivetrain.stop();
 }
 // Called repeatedly when this Command is scheduled to run
 protected void execute() {
   drivetrain.drive(joystick);
 }