An addition to Sidetiq to make it easier to declare the worker's schedule's timezone. Assumes ActiveRecord::TimeZone is available.

## sidetiq_schedule_time_zone_additions.rb
# Timezone extension to Sidetiq
Sidetiq::Schedulable::ClassMethods.class_eval do
  # Sets the time zone for the recurrence rules.
  #
  # Example:
  #
  #   class MyWorker
  #     include Sidekiq::Worker
  #     include Sidetiq::Schedulable
  #
  #     schedule_time_zone "Australia/Perth"
  #
  #     recurrence do
  #       daily.hour_of_day(13)
  #     end
  #
  #     def perform
  #       puts "It's 1pm in Perth"
  #     end
  #   end
  def schedule_time_zone(time_zone_name)
    zone = ActiveSupport::TimeZone[time_zone_name]

    # We use 2010-1-1 for the start time because that's what Sidetiq uses, and
    # you probably need it to be in the past to do backfilling
    schedule.start_time = zone.local(2010, 1, 1)
  end
end

Sidetiq::Schedule.class_eval do
  # Returns the time_zone for the schedule. Handy in Rspec assertions to
  # verify that a worker's schedule is using the right timezone.
  def time_zone
    start_time.time_zone
  end
end