FIX: Remove old reference and use `MiniScheduler::Stat`.

app/jobs/scheduled/weekly.rb

@@ -11,7 +11,7 @@ module Jobs
       Post.calculate_avg_time
       Topic.calculate_avg_time
       ScoreCalculator.new.calculate
-      SchedulerStat.purge_old
+      MiniScheduler::Stat.purge_old
       Draft.cleanup!
       UserAuthToken.cleanup!
     end

app/models/scheduler_stat.rb

@@ -1,21 +0,0 @@
-class SchedulerStat < ActiveRecord::Base
-  def self.purge_old
-    where('started_at < ?', 1.months.ago).delete_all
-  end
-end
-
-# == Schema Information
-#
-# Table name: scheduler_stats
-#
-#  id                :integer          not null, primary key
-#  name              :string           not null
-#  hostname          :string           not null
-#  pid               :integer          not null
-#  duration_ms       :integer
-#  live_slots_start  :integer
-#  live_slots_finish :integer
-#  started_at        :datetime         not null
-#  success           :boolean
-#  error             :text
-#