FIX: sidekiq 100% CPU usage due to `ice_cube`

app/jobs/scheduled/poll_mailbox.rb

@@ -6,7 +6,7 @@ require_dependency 'email/receiver'
 
 module Jobs
   class PollMailbox < Jobs::Scheduled
-    recurrence { minutely(5) }
+    recurrence { hourly.minute_of_hour(0,5,10,15,20,25,30,35,40,45,50,55) }
     sidekiq_options retry: false
 
     def execute(args)

lib/freedom_patches/ice_cube.rb

@@ -0,0 +1,16 @@
+module IceCube
+  class MinutelyRule < ValidatedRule
+    def initialize(interval = 1, week_start = :sunday)
+      super
+
+      unless interval == 1
+        raise "Due to a gigantic awful bug in ice_cube, don't specify an interval for minutely. Use `hourly.minute_of_hour`"
+      end
+
+      interval(interval)
+      schedule_lock(:sec)
+      reset
+    end
+  end
+end
+