refactor created at filter to use model scopes

app/finders/created_at_filter.rb

+module CreatedAtFilter
+  def by_created_at(items)
+    items = items.created_before(params[:created_before]) if params[:created_before].present?
+    items = items.created_after(params[:created_after]) if params[:created_after].present?
+
+    items
+  end
+end

app/finders/issuable_finder.rb

@@ -19,7 +19,7 @@
 #     iids: integer[]
 #
 class IssuableFinder
-  include Gitlab::Database::CreatedAtFilter
+  include CreatedAtFilter
   
   NONE = '0'.freeze
   IRRELEVANT_PARAMS_FOR_CACHE_KEY = %i[utf8 sort page].freeze
@@ -38,6 +38,7 @@ class IssuableFinder
   def execute
     items = init_collection
     items = by_scope(items)
+    items = by_created_at(items)
     items = by_state(items)
     items = by_group(items)
     items = by_search(items)
@@ -49,7 +50,6 @@ class IssuableFinder
     items = by_iids(items)
     items = by_milestone(items)
     items = by_label(items)
-    items = by_created_at(items)
 
     # Filtering by project HAS TO be the last because we use the project IDs yielded by the issuable query thus far
     items = by_project(items)

app/finders/users_finder.rb

@@ -15,7 +15,7 @@
 #     skip_ldap: boolean
 #
 class UsersFinder
-  include Gitlab::Database::CreatedAtFilter
+  include CreatedAtFilter
 
   attr_accessor :current_user, :params
 

app/models/concerns/created_at_filterable.rb

+module CreatedAtFilterable
+  extend ActiveSupport::Concern
+
+  included do
+    scope :created_before, ->(date) { where(scoped_table[:created_at].lteq(date)) }
+    scope :created_after, ->(date) { where(scoped_table[:created_at].gteq(date)) }
+
+    def self.scoped_table
+      arel_table.alias(table_name)
+    end
+  end
+end

app/models/issue.rb

@@ -13,6 +13,7 @@ class Issue < ActiveRecord::Base
   include FasterCacheKeys
   include RelativePositioning
   include IgnorableColumn
+  include CreatedAtFilterable
 
   ignore_column :position
 

app/models/user.rb

@@ -12,6 +12,7 @@ class User < ActiveRecord::Base
   include TokenAuthenticatable
   include IgnorableColumn
   include FeatureGate
+  include CreatedAtFilterable
 
   prepend EE::GeoAwareAvatar
   prepend EE::User

lib/gitlab/database/created_at_filter.rb

-module Gitlab
-  module Database
-    module CreatedAtFilter
-      def by_created_at(items)
-        if params[:created_after].present?
-          items = items.where(items.klass.arel_table[:created_at].gteq(params[:created_after]))
-        end
-
-        if params[:created_before].present?
-          items = items.where(items.klass.arel_table[:created_at].lteq(params[:created_before]))
-        end
-
-        items
-      end
-    end
-  end
-end