+. Initializing the shared repository with `git-init-db --shared`
+helps somewhat.
+
+. Run the following in the shared repository:
++
+------------
+$ chgrp -R $group repo.git
+$ find repo.git -type d -print | xargs chmod ug+rwx,g+s
+$ GIT_DIR=repo.git git repo-config core.sharedrepository true
+------------
+
+The above measures make sure that directories lazily created in
+`$GIT_DIR` are writable by group members. You, as the
+repository administrator, are still responsible to make sure
+your developers belong to that shared repository group and set
+their umask to a value no stricter than 027 (i.e. at least allow
+reading and searching by group members).
+