Goals:
Start to learn Kotlin
Try some Akka, Java, Kotlin "K"ooperation.
Elevators' logic is interesting.
Elevator is an actor. There is a thin and simple HTTP layer.
curl localhost:8080/call/0
Call elevator to floor #0
curl localhost:8080/goto/5
Ask elevator to go to floor #5. At reaching the target floor
it will open the doors and close them after.
curl localhost:8080/stop
Gracefully stop the service and start using stairs.
Take a look at tests and logs. The most interesting dynamic and async part
of action happens there.