build file? install rails app?

In java ANT is used to build java applications. For a RoR application,
is there anything which does remotely the same thing?

Because I wanted a repeatable process I created a ruby script which:

1. drops then creates the db
2. deletes the directory
3. does all the "rails", "rake", "script/server" commands
4. modifies the database.yml and class files
5. starts WEBrick

I like the idea, but it's impossibly kludgy, fragile and spammy.
However, it does accomplish the purpose of serving as documentation for
me to recreate another rails project.

Once you have something mocked up to the point where you can do some data
entry, and maybe a query, what then? At certain stages "script/server
migrate", "rake db:migrate" or "script/server scaffold <model>
<controller>" would need to be re-run.

How do you know which one to do and when? I guess since it "works" I
fear breaking it! Of course, it will break, repeatedly, as I learn how
to use rails, but...

Just looking for pointers.

Also, what I'm interested in doing would be a rails application for which
there's a "one click installer" for. Is this possible? I'm working
towards an RSS aggregator and would like to offer a one-click-install
(meaning a ruby build file) to at least get the ruby parts working.

I wouldn't want to be able to install rails itself nor the database, just
the rails application itself. I guess, in Gentoo, that might be
accomplished with an ebuild?

Ahem, also: how do you get rails to "do" something? By which I mean
have a button/link/whatever which would cause the rails app to run the
ruby script which would grab RSS feeds, or web pages, or e-mails from
imap, or what-have-you? There must be some way of starting that from
within rails.