How to loop through versions?

I wasn't sure how to go about doing this, initialy I had some code to the effect of this:

``` ruby
foo.version.downto(1) do |version|
  foo.revert_to(version)
  puts foo.version
end  
```

But I was wondering if there was a direct way of doing it? Doing it this way pollutes foo's scope, so if I wanted to use the most up-to-date foo after the loop finishes executing I have to reload it.
