How to add ruby\bin to your path

How to add ruby\bin to your path:
either do this on the command line thus:
set PATH=c:\ruby-1.9.1-p0-i386-mingw32\bin;%PATH%

or change the PATH variable within my computer -> properties ->
advanced -> environment variables (add it to the front of path within
"system variables").

== How to determine success ==
If successful you should get an output like (for 1.8):

C:\>ruby -v
ruby 1.8.6 (2009-03-31 patchlevel 368) [i386-mingw32]