The short and sweet: you can not, should not, and will not try to save information in memory in your Rails environment across web requests. If you need to save data, use a database, use the session, use flat files on the disk. Expecting Ruby to "just remember" is pointless here because 1) yes, development environment reloads everything on each request and 2) production deploy environments run mutiple instances of Rails processes so you're never guarenteed to get the same process for subsequent requests.
Jason