I have added the repository "Ruby Extensions (openSUSE_Tumbleweed)" to
my system. Trying to install ruby2.2-rubygem-jekyll results in an error:

# zypper in ruby2.2-rubygem-jekyll
[...]

Problem: nothing provides rubygem(ruby:2.2.0:rouge:1) >= 1.7 needed by
ruby2.2-rubygem-jekyll-3.1.2-1.1.x86_64
 Solution 1: do not install ruby2.2-rubygem-jekyll-3.1.2-1.1.x86_64
 Solution 2: break ruby2.2-rubygem-jekyll-3.1.2-1.1.x86_64 by ignoring some of
its dependencies

But rubygem-rouge is only available in some home projects.