This allows anyone to visit the URL and be added to a (hopefully read-only) team. Uses PHP 7 and Redis/Memcached.

• GITHUB_CLIENT_ID - Your GitHub applications's client ID.
• GITHUB_CLIENT_SECRET - Your GitHub application's client secret.
• GITHUB_USER_TOKEN - A personal access token with the admin:org permission.
• GITHUB_TEAM - The ID of the team people should be added to.
• GITHUB_CALLBACK - The callback URL to redirect from GitHub to.