Ruby Gem package guidelines
For libraries, use
ruby-gemname. For applications, use the program name. In either case, the name should be entirely lowercase
For examples, please seeAUR AUR AUR.
--verbose to gem arguments to recive additional information in case of troubles.
An example PKGBUILD can be found at
/usr/share/pacman/PKGBUILD-rubygem.proto, which is in the package.
There are also multiple gem2arch tools which aid in automating the process of creating a ruby gem PKGBUILD. Make sure to manually check the PKGBUILD after generation. The original version is by Abhishek Dasgupta. Search for other versions of this tool in AUR (Search for gem2arch).