reference models by URI for Ruby on Rails

 A Global ID is an app wide URI of the form gid://YourApp/Some::Model/id
 that uniquely identifies a model instance.
 .
 This is helpful when you need a single identifier to reference different
 classes of objects, for example in job scheduling, when one needs to reference
 a model object rather than serialize the object itself. Another example is a
 drop-down list of options, consisting of both Users and Groups. One has then a
 universal identifier that works for objects of both classes.
 .
 This package is part of the dependencies for the Ruby on Rails framework.