Small C program to run any .sh script as root.
Compile the file running the compile.sh script this will automatically add root as the file owner and give the setuid permission to the compiled file.
The file will always try to execute a file with the same name as it appending the .sh extension, you can rename it to whatever you want.
For example rename it to post-receive and save it into the git repository, then create a file called post-receive.sh and do anything you want in there.