1. Go to your Toribash Folder > data > scripts
2. Create a new file zzz with the Lua extension (zzz.lua)
3. Open Toribash > Setup > Scripts, and the Worldbuilder.lua script will appear !
It's only because the last script in alphabetical order doesn't appear on the list. So if you just put an a in front of Worlbuilder.lua to make it aWorldbuilder.lua then it should show up.