reorder method added to ActiveRelation

[#4972 state:committed]

Signed-off-by: José Valim <jose.valim@gmail.com>

activerecord/lib/active_record/relation/query_methods.rb

@@ -21,6 +21,14 @@ def #{query_method}(*args, &block)
         CEVAL
       end
 
+      def reorder(*args, &block)
+        new_relation = clone
+        new_relation.send(:apply_modules, Module.new(&block)) if block_given?
+        value = Array.wrap(args.flatten).reject {|x| x.blank? }
+        new_relation.order_values = value if value.present?
+        new_relation
+      end
+
       def select(*args)
         if block_given?
           to_a.select { |*block_args| yield(*block_args) }

activerecord/test/cases/relations_test.rb

@@ -116,6 +116,12 @@ def test_finding_with_order_concatenated
     assert_equal topics(:fourth).title, topics.first.title
   end
 
+  def test_finding_with_reorder
+    topics = Topic.order('author_name').order('title').reorder('id')
+    assert_equal 4, topics.to_a.size
+    assert_equal topics(:first).title, topics.first.title
+  end
+
   def test_finding_with_order_and_take
     entrants = Entrant.order("id ASC").limit(2).to_a