OP commented here, but didn't respond to you. They most likely went with Symfony since the original codebase was PHP. Porting to Symfony2 gives modern MVC web app framework tools and structure but has the same environment requirements. So there is very little cost as opposed to switching languages. The Ruby deployment methodology most likely uses Capifony a special extension to the Capistrano ruby gem for deployment built around Symfony and Symfony2.
