problem installing gnustep-ruby

[enrico donelli]

Hello everybody,
I installed two days ago GNUstep, and everything went fine.
I would like to study the ruby binding, so I downloaded the package
gnustep-ruby, but during the compilation i get the following error:

/usr/bin/ld: cannot find -lgmodel
collect2: ld returned 1 exit status

On my system I couldn't find the libgomdel.so library, but only the
file: 

/opt/GNUstep/System/Library/Bundles/libgmodel.bundle/ix86/linux-gnu/gnu-gnu-gnu/libgmodel:
 ELF 32-bit LSB shared object, Intel 80386, version 1, not stripped


which package does libgmodel belong? 
What do I need to properly install gnustep-ruby?

Thanks a lot for the really god job you are making and for any help!!

Enrico