Move PubSubHubbub pinging to a background worker

It can take as much as 0.5s if not longer to complete

app/workers/hub_ping_worker.rb

@@ -0,0 +1,9 @@
+class HubPingWorker
+  include Sidekiq::Worker
+  include RoutingHelper
+
+  def perform(account_id)
+    account = Account.find(account_id)
+    account.ping!(account_url(account, format: 'atom'), [Rails.configuration.x.hub_url])
+  end
+end