Sort by ID when sorting using "Recently created"

Sorting by "id" has the same effect as sorting by created_at while
performing far better and without the need of an extra index (in case
one wanted to speed up sorting by "created_at").

Sorting by "Recently updated" still uses the physical "updated_at"
column as there's no way to use the "id" column for this instead.

app/controllers/application_controller.rb

@@ -286,7 +286,7 @@ class ApplicationController < ActionController::Base
   end
   def set_filters_params
-    params[:sort] ||= 'created_desc'
+    params[:sort] ||= 'id_desc'
     params[:scope] = 'all' if params[:scope].blank?
     params[:state] = 'opened' if params[:state].blank?

app/helpers/sorting_helper.rb

@@ -63,11 +63,11 @@ module SortingHelper
   end
   def sort_value_oldest_created
-    'created_asc'
+    'id_asc'
   end
   def sort_value_recently_created
-    'created_desc'
+    'id_desc'
   end
   def sort_value_milestone_soon

app/models/concerns/sortable.rb

@@ -11,6 +11,7 @@ module Sortable
     default_scope { order_id_desc }
     scope :order_id_desc, -> { reorder(id: :desc) }
+    scope :order_id_asc, -> { reorder(id: :asc) }
     scope :order_created_desc, -> { reorder(created_at: :desc) }
     scope :order_created_asc, -> { reorder(created_at: :asc) }
     scope :order_updated_desc, -> { reorder(updated_at: :desc) }
@@ -28,6 +29,8 @@ module Sortable
       when 'updated_desc' then order_updated_desc
       when 'created_asc' then order_created_asc
       when 'created_desc' then order_created_desc
+      when 'id_desc' then order_id_desc
+      when 'id_asc' then order_id_asc
       else
         all
       end