Insufficient permission for adding an object to repository database

Problem: Insufficient permission for adding an object to repository database

Solution:
git config core.sharedRepository group

cd /path/to/repo.git
chgrp -R groupname .
chmod -R g+rwX .
find . -type d -exec chmod g+s ‘{}’ +

Reference:
https://stackoverflow.com/questions/6448242/git-push-error-insufficient-permission-for-adding-an-object-to-repository-datab