Go-Fish Gamemode

Is there an addon version of Go-Fish anywhere? It would be a great addon rather than a gamemode, and if there isn’t one out there already, could I get an estimate on how hard it would be to code it to be an addon (if even possible?). Thank you in advance.

why would u want it to be a addon. whats wrong with a gamemode?
heres a svn link - http://gmodes.googlecode.com/svn/trunk/gamemodes/Go_Fish/
make a folder in your addons and use svn updater or w/e to download the content to the file and there u go, a go-fish addon file but it will just end up merging into gamemodes anyway

I would like an add-on form so you can attatch it to a gamemode like Dark RP and just have it on the side. And your instructions are a little confusing to me, can you explain it in like steps?