Binary package “ruby-gtk3” in ubuntu bionic

GTK+ 3 bindings for the Ruby language

 GTK+ is a multi-platform toolkit for creating graphical user interfaces.
 Offering a complete set of widgets, GTK+ is suitable for projects ranging
 from small one-off tools to complete application suites.
 .
 This package contains libraries for using GTK+ 3 with the Ruby programming
 language.