https://github.com/gavrielk/jenkins.git

commit:

1. change a file
2. git add README.md //add to local git repository
3. git commit -m "blabla" //commit to local repository
4. git push origin master //deliver to online repository

update:

1. git fetch upstream //update repository, origin on work comp, upstream on laptop
2. git merge origin/master //merge local and updated repository