The official Rails job board is live
rubyonrails.org
rubyonrails.org
I think there's room for such a service, but growing it into a viable model would be a real project, and probably not a distraction a business would want to take on except as a pivot.
Job boards want the potential employees to need to respond to job adverts, which are paid for.
This would have made many millions had it been launched day one. Finding Rails people has always been a nightmare - at least where i live.
Recruiters and employers have a budget to spend on job ads.
Often what happens with there job boards is they start with "no recruiters!", then they move to "no recruiters, unless you say full details of the job", then they realise just how much money recruiters have in the budget to spend on job ads (it's alot), and they give up the principles and happily take the recruiter cash.