Best Way to redirect a site

I have one ruby on rails application but multiple domains for this app., etc. I only need one application hosted in dreamhost, yet when someone visits from a different www address i want them to see the same content. What is the best way to do this ? CNAME redirect? Is it even possible?

(i.e. when someone goes to you will still see in your address bar, but the site will be rendering This is how my former/current host does things but i can’t figure out how to do it with dreamhost.

Have one domain mirror the other. Read about it here: