best way to freeze Rails?

Is there a best way to freeze Rails apps these days? WRT the github
hosting. Bear in mind I'm still learning my around Git.

I tried:
git clone git://github.com/rails/rails.git
git checkout 2-1-stable

but it didn't seem to work, since "head railties/CHANGELOG" showed the
2.1.1 changelog. In addition a "git pull" caused a list of merge
errors.

So I found a different approach:
cd (RAILS_ROOT)/vendor
wget http://github.com/rails/rails/tarball/v2.1.0
tar xvzf rails-rails-71528b1825ce5184b23d09f923cb72f4073ce8ed.tar.gz
mv rails-rails-71528b1825ce5184b23d09f923cb72f4073ce8ed rails
rm rails-rails-71528b1825ce5184b23d09f923cb72f4073ce8ed.tar.gz

While the latter works cleanly, it seems a bit clunky. Wondering if
maybe there's an elegant Git solution that I'm just not aware of.

thank you kindly,

rake rails:freeze:gems should still work, afaik.

Jeff