ruby-warden binary package in Ubuntu Xenial amd64

 Warden is a Rack-based middleware, designed to provide a mechanism for
 authentication in Ruby web applications. It is a common mechanism that
 fits into the Rack Machinery to offer powerful options for authentication.
 .
 Warden is designed to be lazy. That is, if you don't use it, it doesn't
 do anything, but when you do use it, it will spring into action and
 provide an underlying mechanism to allow authentication in any
 Rack-based application.

Source package