Adding embedded PuSH server

app/services/pubsubhubbub/unsubscribe_service.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class Pubsubhubbub::SubscribeService < BaseService
+  def call(account, callback)
+    return ['Invalid topic URL', 422] if account.nil?
+
+    subscription = Subscription.where(account: account, callback_url: callback)
+
+    unless subscription.nil?
+      Pubsubhubbub::ConfirmationWorker.perform_async(subscription.id, 'unsubscribe')
+    end
+
+    ['', 202]
+  end
+end