cartage-rack 2.3

This release is the *last* version of cartage-rack. It will be replaced with a different tool in the future, but this release will allow installation in modern Ruby versions. cartage-rack is a plug-in for {cartage}[https://github.com/KineticCafe/cartage] to provide a Rack application that reports on release metadata. Cartage provides a repeatable means to create a package for a Rails application that can be used in deployment with a configuration tool like Ansible, Chef, Puppet, or Salt. The package is created with its dependencies bundled in +vendor/bundle+, so it can be deployed in environments with strict access control rules and without requiring development tool access.