How module the world with elixir

module_world.ex

1. How to distiguish the same object?
We use tuple which consist of type and ID
def init({db_folder, pool_size}) do
    processes = for worker_id <- 1..pool_size do
      worker(
        Todo.DatabaseWorker, [db_folder, worker_id],
        id: {:database_worker, worker_id} 
      )
    end

    supervise(processes, strategy: :one_for_one)
  end