GitHub is a great source of third-party addons. A lot of Odoo partners use GitHub to share the addons they maintain internally, and the Odoo Community Association (OCA) collectively maintains several hundreds of addons on GitHub. Before starting to write your own addon, ensure that you check that nothing already exists that you can use as is or as a starting point.

This recipe will show you how to clone the partner-contact project of the OCA from GitHub and make the addon modules it contains available in your instance.