= Description
Rack middleware that authenticates requests with matching username and password

= Prerequisites
rack 1.0.0 or later

= Usage
use "Rack::Auth::Cheat", "user_field", "password_field"

= Default Fields
The default user field is "username".
The default password field is "password".

= Details
The rack-auth-cheat library provides a Rack middleware interface which authenticates
any request with a matching username and password. This is useful in development
environments, especially as a way to stub out an external authentication system. Be
sure to include this from an environment-specific file such as
config/environments/development.rb rather than from a global configuration file such
as config/environment.rb

The call method we've defined first checks to see if the AUTH_USER
environment variable is set. If it is, we assume that the user has
already been authenticated and move on.

If AUTH_USER is not set, and AUTH_FAIL is not set, we then check whether
the username and password match (the "Cheat" authentication method). If
they match, AUTH_USER is set to the username.

If they don't match then the request is passed on without modification.
AUTH_FAIL will not be set by this class.

It up to the application to check for the presence of AUTH_USER and/or
AUTH_FAIL and act as necessary.

= Authors
Daniel Berger
Charlie O'Keefe