To use the build system : 

- create a user (nightly) 
- create 2 folders in his home : buildroot and www
- point a virtualhost into www in your webserver
- copy build.sh to the home and the other files to www
- launch build.sh when you want to build the packages

You may need to change the pgp-key-id into build.sh (2 times) and into nightly.key