feat: add join form

lib/mv/application.ex

@@ -9,6 +9,7 @@ defmodule Mv.Application do
   alias Mv.Repo
   alias Mv.Vereinfacht.SyncFlash
   alias MvWeb.Endpoint
+  alias MvWeb.JoinRateLimit
   alias MvWeb.Telemetry
 
   @impl true
@@ -18,6 +19,7 @@ defmodule Mv.Application do
     children = [
       Telemetry,
       Repo,
+      {JoinRateLimit, [clean_period: :timer.minutes(1)]},
       {Task.Supervisor, name: Mv.TaskSupervisor},
       {DNSCluster, query: Application.get_env(:mv, :dns_cluster_query) || :ignore},
       {Phoenix.PubSub, name: Mv.PubSub},