From https://once.com/writebook

app/controllers/accounts/join_codes_controller.rb

@@ -0,0 +1,8 @@
+class Accounts::JoinCodesController < ApplicationController
+  before_action :ensure_can_administer
+
+  def create
+    Current.account.reset_join_code
+    redirect_to users_path
+  end
+end