routing subdomain request

Give how to do this trick:    1. Users were tables with one of the fields and table subdomain     Blogs class Blog <ActiveRecord:: Base        has_many: comments        belongs_to: user    class User <ActiveRecord:: Base       has_many: blogs   2. There is a module which writes in account_subdomain subdomain address from the browser   3. The objective to have at domain.com / blogs drawing record all users, and sub.domain.com/blogs write only user's subdomain which "sub" How? Thanks!