Why my rails command works differently with system() than in terminal?

The command that I'm trying to run is rails _3.2.13_ new App

When I run it in command line it creates a Rails app with version 3.2.13, but when I run it with system "rails _3.2.13_ new #{self.name} -T -B" it creates a Rails app with the latest version of Rails not 3.2.13 version.