Fix regeneration marker not expiring (#6290)

* Fix regeneration key not getting expired

* Add rake task to remove old regeneration markers

spec/controllers/concerns/user_tracking_concern_spec.rb

@@ -69,6 +69,12 @@ describe ApplicationController, type: :controller do
         expect(RegenerationWorker).to have_received(:perform_async)
       end
 
+      it 'sets the regeneration marker to expire' do
+        allow(RegenerationWorker).to receive(:perform_async)
+        get :show
+        expect(Redis.current.ttl("account:#{user.account_id}:regeneration")).to be >= 0
+      end
+
       it 'regenerates feed when sign in is older than two weeks' do
         get :show