When you want to have a central shared git repository to push commits to, there are two common configurations:

1. Everybody uses the same user for commits - easy to set up, but very messy,

2. Create a system user for each committer, create a system group for each project and add users to relevant groups.

Below is an explanation of how to set up and manage configuration 2.

Create User 'git'

Create a 'user 'git' to manage projects.

$ sudo useradd --shell /bin/bash --home-dir /var/git --create-home git

A Directory for Repositories

$ sudo su - git
$ mkdir /var/git/repositories

Create a Project

$ cd /var/git/repositories
$ mkdir [PROJECT_NAME]
$ cd [PROJECT_NAME]
$ git --bare init

Create a group for the project:

$ sudo groupadd [PROJECT_NAME]

Add relevant users to the group:

$ sudo usermod --append --groups [GROUP_NAME] [USER_NAME]

Give the group write permissions to the repository:

$ sudo chgrp -R [GROUP_NAME] /var/git/repositories/[REPOSITORY_PATH]
$ sudo chmod -R ug+w /var/git/repositories/[REPOSITORY_PATH]
$ chmod -R o-w /var/git/repositories/[REPOSITORY_PATH]

Have Git Handle Group Permissions

In .git/config:

[core]
  sharedrepository = 1

Use

Now, when you use the remote shared repository, you can use your personal account:

$ git clone ssh://my-user@example.com/path/to/repo