This is a different project at Github.
Like the one for Windows, this merges your Shoes App into a copy of Shoes, removes things you don’t want users to get to or know about like the manual, or Cobbler or packaging. For linux this means your app will installed in /usr/local/[lib|bin] or /usr/[lib|bin|]. Your choice. Any gems need by your script will be inside the ruby in your app. Because you decided what gems to include. No need to code Shoes.setup and have your users wait for it to download – you’ve included them. If you want a menu entry and and an Icon to match, it’s your choice.
There are implications you may not have thought of and there’s a long list of bewares and much testing for you because you have choices and responsibilities for those choices. Neither I nor Shoes will make those choices for you. There’s no GUI to make it appear simple. Because it’s not simple. It’s not overly hard but it’s not simple.
Currently it only builds .deb and Ubuntu 14.04 likes them but Ubuntu 15.10 whines about something in the maintainer field (and then installs it if you tell it too). That’s a setting you control and obviously you have to test for the platforms you care about. Maybe you need a .ppa and an account with Ubuntu. Every platform and distribution now days has it’s rules. Shoes can’t do that for you. You may have to modify the scripts to do what you want. ‘rpm’ is an easy option. Other formats (arch, suse …) just slightly more difficult once you know the packaging tools and read the script – it’s only 210 lines of ruby.