Create rake task to migrate Setting key from per_page_code to per_page_code_head

lib/tasks/settings.rake

@@ -0,0 +1,11 @@
+namespace :settings do
+
+  desc "Changes Setting key per_page_code for per_page_code_head"
+  task per_page_code_migration: :environment do
+    per_page_code_setting = Setting.where(key: 'per_page_code').first
+
+    Setting['per_page_code_head'] = per_page_code_setting&.value.to_s if Setting.where(key: 'per_page_code_head').first.blank?
+    per_page_code_setting.destroy if per_page_code_setting.present?
+  end
+
+end