Make gem compatible with non-Rails Ruby frameworks

These small fixes will make the gem compatible with non-Rails Ruby frameworks like Sinatra.

Please note that this gem was never pushed to Rubygems, and so I pushed it myself: http://rubygems.org/gems/login_radius. I can transfer ownership if I you supply me with the e-mail of one of your developers: http://guides.rubygems.org/command-reference/#owner

As a suggestion, I also recommend changing the name of the repository to something like `loginradius-rb` or `loginradius-ruby` to facilitate searching for it. `Ruby-on-rails-gem` is not very descriptive nor SEO-friendly.