How to use the decentraland-ecs/src.engine.addSystem function in decentraland-ecs

}
}
let rotatingCubes = engine.getComponentGroup(ObjectRotation)

export class ObjectRotationSystem implements ISystem {
  update(dt: number) {
    for (let cubeEntity of rotatingCubes.entities) {
      let rotationComponent = cubeEntity.getComponent(ObjectRotation)

      let transform = cubeEntity.getComponent(Transform)
      transform.rotate(rotationComponent.rotationAxis, rotationComponent.speed * dt)
    }
  }
}
let rotationSystem = new ObjectRotationSystem()
engine.addSystem(rotationSystem)

let rotatingPlatformEntity = new Entity()
rotatingPlatformEntity.addComponentOrReplace(new BoxShape())
rotatingPlatformEntity.addComponentOrReplace(
  new Transform({
    position: new Vector3(2, 1, 2),
    scale: new Vector3(5, 0.25, 1.5)
  })
)
rotatingPlatformEntity.addComponentOrReplace(new ObjectRotation(10, new Vector3(0, 1, 0)))
engine.addEntity(rotatingPlatformEntity)

if(this.shouldSwitchDirection(movementData)) {
          movementData.goingForward = !movementData.goingForward
        }

        movementData.targetWaypoint = movementData.currentWaypoint + (movementData.goingForward ? 1 : -1)
      }
    }
  }

  shouldSwitchDirection (movementData: PathMovement) {
    return  (movementData.goingForward && movementData.currentWaypoint == movementData.waypoints.length - 1) ||
            (!movementData.goingForward && movementData.currentWaypoint == 0)
  }
}
let movementSystem = new PingPongMovementSystem()
engine.addSystem(movementSystem)

export function configureShapeEntityPositions(waypointsPath: Vector3[], speed: number, shape: Shape) {
  const entity = new Entity()
  entity.addComponentOrReplace(shape)
  entity.addComponentOrReplace(
    new Transform({
      position: waypointsPath[0]
    }))

  entity.addComponentOrReplace(new PathMovement(waypointsPath, speed))

  engine.addEntity(entity)
  return entity
}

configureShapeEntityPositions([new Vector3(-3, 1, -8), new Vector3(35, 1, -8)], 0.2, new NFTShape('ethereum://0x06012c8cf97BEaD5deAe237070F9587f8E7A266d/558536'))