This is a programming forum, not a job marketplace
The description of the group is "The official mailing list for the Ruby on Rails project. Where Rails users come to seek help, announce projects, and discuss all kind of matters surrounding the framework and the community." I don't think that precludes job related information, within reason.
In fact what I find more annoying is when someone posts a question and then re-posts the same question a few hours later, or posts a further question which implies that they have solved the problem but have not posted a follow-up to the original indicating the solution.