This group is for builders of Rails apps, from independent devs, to small teams, to small business teams: just be actually building something. Get together with other builders, collaborate, pair program, discuss deployment platforms, and participate in hacking sessions.
This group is not for tutorials, or people looking primarily for a "teach me Rails" group. This group is for builders, not simply people playing around with the framework, or evaluating Rails in a cursory manner.
So do you have to be a Rails expert to join this group? No. You can even be somewhat of a beginner. Just be working on an actual project that you plan on deploying to actual servers.