- What’s GitHub?
GitHub is a code hosting platform for version control and collaboration. It lets you and others work together on projects from anywhere.


- What’s a Repository?
A repository is usually used to organize a single project. Repositories can contain folders and files, images, videos, spreadsheets, and data sets – anything your project needs.


- What’s a branch?
Branching is the way to work on different versions of a repository at one time.

By default your repository has one branch named master which is considered to be the definitive branch. We use branches to experiment and make edits before committing them to master.

When you create a branch off the master branch, you’re making a copy, or snapshot, of master as it was at that point in time. If someone else made changes to the master branch while you were working on your branch, you could pull in those updates.

Have you ever saved different versions of a file? Something like:

story.txt
story-joe-edit.txt
story-joe-edit-reviewed.txt

Branches accomplish similar goals in GitHub repositories.

Here at Odoo, our developers use branches for keeping bug fixes and feature work separate from our master (production) branch. When a change is ready, they merge their branch into master.

- What’s a commit?
On GitHub, saved changes are called commits. Each commit has an associated commit message, which is a description explaining why a particular change was made. Commit messages capture the history of your changes, so other contributors can understand what you’ve done and why.


- What’s a pull request?
Pull Requests are the heart of collaboration on GitHub. When you open a pull request, you’re proposing your changes and requesting that someone review and pull in your contribution and merge them into their branch. Pull requests show diffs, or differences, of the content from both branches. The changes, additions, and subtractions are shown in green and red.

- GitHub flow (introduction)
https://guides.github.com/introduction/flow/