Set up custom domains for users using rails 4, nginx with passenger
What you're looking for is something called "virtual subdomains" (I think). Here is some information about how to set them up:
- http://signalvnoise.com/posts/1512-how-to-do-basecamp-style-subdomains-in-rails
- Rails Restful Routing and Subdomains
You basically need to set up a "wildcard" subdomain in your DNS (which will route all subdomain requests to your app), and let the routing middleware handle the request (& route accordingly)
Domains
Considering the updates, I have had a look online for you:
I don't have experience of this directly, but I'd say you first need to get the domain to point to your site (with CNAME changes). This could then be caught by your routing middleware (as described in the link above), allowing you to "route" the request accordingly
Heroku does this exact thing - it's quite common