Git: auto pull from repository?

Git has "hooks", actions that can be executed after other actions. What you seem to be looking for is "post-receive hook". In the github admin, you can set up a post-receive url that will be hit (with a payload containing data about what was just pushed) everytime somebody pushes to your repo.

For what it's worth, I don't think auto-pull is a good idea -- what if something wrong was pushed to your branch ? I'd use a tool like capistrano (or an equivalent) for such things.

On unix-likes you can create cron job that calls "git pull" (every day or every week or whatever) on your machine. On windows you could use task scheduler or "AT" command to do the same thing.

There are continuous integrations programs like Jenkins or Bamboo, which can detect commits and trigger operations like build, test, package and deploy. They do what you want, but they are heavy with dependencies, hard to configure and in the end they may use periodical check against git repository, which would have same effect like calling git pull by cron every minute.