ruby-builder binary package in Ubuntu Xenial amd64

 Builder is a library that allows easy programmatic creation of XML markup. It
 gives you a Ruby API to build structures and methods to dump it to XML.
 Some of the features:
  * Easy generation by mapping method calls to elements, arguments to
    attributes and blocks to contents.
  * XML comment & processing instruction support.
  * XML entity declaration support.
  * Some support for XML namespaces.
  * Default escaping of string attribute values.
  * UTF-8 support.

Source package