GIT over SSH will create files with user:group from the user that’s doing the push. This will prevent other users from changing files, in particular updating refs/heads/.
To share a GIT repo over SSH among several users, create the repo with –shared=group and put all users in the same primary group:
To fix sharing for an already existent setup, fixup the primary groups and file ownership:
where 1006 is the ID of the ‘git’ group and 1007 and 1008 refer to the user’s respective groups.