fixup

lib/manager.ex

@@ -0,0 +1,17 @@
+defmodule Manager do
+  use DynamicSupervisor
+
+  def start_link(init_arg) do
+    DynamicSupervisor.start_link(__MODULE__, init_arg, name: __MODULE__)
+  end
+
+  @impl true
+  def init(_init_arg) do
+    DynamicSupervisor.init(strategy: :one_for_one)
+  end
+
+  def create_broker(port) do
+    spec = {Broker, port}
+    DynamicSupervisor.start_child(__MODULE__, spec)
+  end
+end