Auto completion in Eclipse for Watir library

Hi,
I’m trying to add auto completion in Eclipse when writing watir code.
I could do it by manually adding the gem folder to “Ruby Load Path” ->
Libraries -> “Add External Folders” - >
“C:\Ruby\lib\ruby\gems\1.8\gems\watir-1.6.5”

The problem is every time I create a new project I need to add it and if
we change the watir version we need to change in all projects the
library folder

Is there any other way?

thanks.