restful_authentication

In the case of two setting files for new user account varidation,

1, vendor/plugin/restful_authentication/lib/authentication.rb

  self.login_regex       = /\A\w[\w\.\-_]+\z@/                     # ASCII, strict

2, lib/restful_authentication/authentication.rb

  self.login_regex       = /\A\w[\w\.\-_]+\z/                     # ASCII, strict

then ruby prefers sometimes setting 1 and sometimes setting 2.
It seems depends on the environment.