use ActiveRecord#find_each to prevent memory spikes in our workers

app/controllers/admins_controller.rb

@@ -30,7 +30,7 @@ class AdminsController < ApplicationController
   def weekly_user_stats
     @created_users = User.where("username IS NOT NULL and created_at IS NOT NULL")
     @created_users_by_week =  Hash.new{ |h,k| h[k] = [] }
-    @created_users.each do |u| 
+    @created_users.find_each do |u| 
       unless u.nil?
           @created_users_by_week[u.created_at.beginning_of_week.strftime("%Y-%m-%d")].push("#{u.username}")
         end

app/workers/notify_local_users.rb

@@ -17,7 +17,7 @@ module Workers
       users = User.where(:id => user_ids)
       person = Person.find_by_id(person_id)
 
-      users.each{|user| Notification.notify(user, object, person) }
+      users.find_each{|user| Notification.notify(user, object, person) }
     end
   end
 end

lib/postzord/receiver/local_batch.rb

@@ -60,7 +60,7 @@ class Postzord::Receiver::LocalBatch < Postzord::Receiver
   # return [void]
   def notify_users
     return unless @object.respond_to?(:notification_type)
-    @users.each do |user|
+    @users.find_each do |user|
       Notification.notify(user, @object, @object.author)
     end
   end