Ruby Gem Package Guidelines
1 Package Naming
For libraries, use ruby-gemname. For applications, use the program name. In either case, the name should be entirely lowercase
Add --verbose to gem arguments to recive additional information in case of troubles.
3 Example PKGBUILD
An example PKGBUILD can be found at /usr/share/pacman/PKGBUILD-rubygem.proto, which is in the abs package.
Abhishek Dasgupta wrote gem2arch to aid in automating the process of creating a ruby gem PKGBUILD. Make sure to manually check the PKGBUILD after generation.