Revert renames from a migration

db/post_migrate/20170525140254_rename_all_reserved_paths_again.rb

@@ -104,5 +104,6 @@ class RenameAllReservedPathsAgain < ActiveRecord::Migration
   end
 
   def down
+    revert_renames
   end
 end

lib/gitlab/database/rename_reserved_paths_migration/v1.rb

@@ -29,6 +29,11 @@ module Gitlab
           paths = Array(paths)
           RenameNamespaces.new(paths, self).rename_namespaces(type: :top_level)
         end
+
+        def revert_renames
+          RenameProjects.new([], self).revert_renames
+          RenameNamespaces.new([], self).revert_renames
+        end
       end
     end
   end

spec/lib/gitlab/database/rename_reserved_paths_migration/v1_spec.rb

@@ -51,4 +51,26 @@ describe Gitlab::Database::RenameReservedPathsMigration::V1, :truncate do
       subject.rename_root_paths('the-path')
     end
   end
+
+  describe '#revert_renames' do
+    it 'renames namespaces' do
+      rename_namespaces = double
+      expect(described_class::RenameNamespaces).
+        to receive(:new).with([], subject).
+             and_return(rename_namespaces)
+      expect(rename_namespaces).to receive(:revert_renames)
+
+      subject.revert_renames
+    end
+
+    it 'renames projects' do
+      rename_projects = double
+      expect(described_class::RenameProjects).
+        to receive(:new).with([], subject).
+             and_return(rename_projects)
+      expect(rename_projects).to receive(:revert_renames)
+
+      subject.revert_renames
+    end
+  end
 end