Github
What is GitHub and why is it used?
GitHub is a web-based interface that uses Git, the open source version control software that lets multiple people make separate changes to web pages at the same time. As Carpenter notes, because it allows for real-time collaboration, GitHub encourages teams to work together to build and edit their site content.
What is GitHub application used for?
GitHub Apps are tools that extend GitHub's functionality. GitHub Apps can do things on GitHub like open issues, comment on pull requests, and manage projects. They can also do things outside of GitHub based on events that happen on GitHub. For example, a GitHub App can post on Slack when an issue is opened on GitHub.