Add Sidekiq worker example.

examples/sidekiq_worker.rb

+# This class implements a Sidekiq worker for performing geocoding
+# asynchronously. Do something like this in your controller:
+#
+# if @object.save
+#   GeocoderWorker.perform_async(@object.id)
+# end
+#
+class GeocoderWorker
+  include Sidekiq::Worker
+
+  def perform(object_id)
+    object = Object.find(object_id)
+    object.geocode
+    object.save!
+  end
+end