Eliminate the warnings for database

lib/tasks/migrate/setup_postgresql.rake

-require Rails.root.join('lib/gitlab/database')
-require Rails.root.join('lib/gitlab/database/migration_helpers')
-require Rails.root.join('db/migrate/20151007120511_namespaces_projects_path_lower_indexes')
-require Rails.root.join('db/migrate/20151008110232_add_users_lower_username_email_indexes')
-require Rails.root.join('db/migrate/20161212142807_add_lower_path_index_to_routes')
-require Rails.root.join('db/migrate/20170317203554_index_routes_path_for_like')
-require Rails.root.join('db/migrate/20170724214302_add_lower_path_index_to_redirect_routes')
-require Rails.root.join('db/migrate/20170503185032_index_redirect_routes_path_for_like')
-require Rails.root.join('db/migrate/20171220191323_add_index_on_namespaces_lower_name.rb')
-require Rails.root.join('db/migrate/20180113220114_rework_redirect_routes_indexes.rb')
-
 desc 'GitLab | Sets up PostgreSQL'
 task setup_postgresql: :environment do
+  require Rails.root.join('db/migrate/20151007120511_namespaces_projects_path_lower_indexes')
+  require Rails.root.join('db/migrate/20151008110232_add_users_lower_username_email_indexes')
+  require Rails.root.join('db/migrate/20161212142807_add_lower_path_index_to_routes')
+  require Rails.root.join('db/migrate/20170317203554_index_routes_path_for_like')
+  require Rails.root.join('db/migrate/20170724214302_add_lower_path_index_to_redirect_routes')
+  require Rails.root.join('db/migrate/20170503185032_index_redirect_routes_path_for_like')
+  require Rails.root.join('db/migrate/20171220191323_add_index_on_namespaces_lower_name.rb')
+  require Rails.root.join('db/migrate/20180113220114_rework_redirect_routes_indexes.rb')
+
   NamespacesProjectsPathLowerIndexes.new.up
   AddUsersLowerUsernameEmailIndexes.new.up
   AddLowerPathIndexToRoutes.new.up