We have a single code base and database for all the 3 languages of a certain website:
http://example.com/ - default, no prefix, English
http://example.com/pt - pt prefix, Portuguese
http://example.com/ru - ru prefix, Russian
However, we now want to change the Russian domain to http://example.ru (no prefix)
What's the best way to attain this without affecting the previous domains and urls?