Add `order` method to globalise.

Populating `order` with a translated column name does not currently result in automatic mapping to the translation table.

I've added an `order` method to `ActiveRecord::QueryMethods`, which will map a translated column to the translation table when called with either `order(:title)` or `order(title: :desc)` format.
@simi Good point, I've moved the guard clause to the `order` method.