gollum-lib_rjgit_adapter
Adapter for Gollum to use RJGit at the backend. This adapter is the default when your platform is JRuby, so you need only to gem install gollum and then use gollum normally.
Note: this adapter is new. Although it passes the full test suite for gollum (and gollum-lib), it might well still contain bugs. Please let us know if you encouter any!