Given its recency, is it safe to assume this works for Rails 4.2.0beta? I'm working on a new project for a client and was a little dismayed that both Rails Admin and ActiveAdmin currently have problems with 4.2.0.
I haven't tested it with 4.2.0 beta yet. I can give it a go this weekend and I will add it as an issue on github as well. If you comment on the issue or email me - jon [at] upmin.com - I can make sure to update you on this.