ruby-activemodel binary package in Ubuntu Trusty arm64

 Active Model is a toolkit for building modeling frameworks like
 Active Record and Active Resource. This includes a rich support for
 attributes, callbacks, validations, observers, serialization,
 internationalization, and testing.
 .
 This is empty dependency package which depends on the default Debian
 version of rails framework. If you need to depend on a specific version
 of rails, you need to depend on <package>-VERSION package.

Source package