Never mind.  I took a guess that there might be a special variable that
tracks what files have been loaded.  There is; it's $".

So, by deleting the particular file from $", I was able to force Ruby to
re-load the file and everything worked just fine.

What's even nicer is that the objects that were created maintained their
definitions even after re-loading.  Only new objects created had the new
definition, which is how I'd like it to be.

As usual, Ruby's approach is just so neat and there were no surprises :-)
!!