message: Add docs for creating a GitHub OAuth application
diff: @@ -27,6 +27,16 @@ export AUTH_GOOGLE_CLIENT_SECRET=x
  ### Github
  +#### Creating a GitHub OAuth application
  +
  +Follow this link, [Create new OAuth App](https://github.com/settings/applications/new).
  +
  +1. Set Application Name to `backstage-dev` or something along those lines.
  +1. You can set the Homepage URL to whatever you want to.
  +1. The Authorization Callback URL should match the redirect URI set in Backstage.
  + 1. Set this to `http://localhost:7000/auth/github` for local development.
  + 1. Set this to `http://{APP_FQDN}:{APP_BACKEND_PORT}/auth/github` for non-local deployments.
  +
  ```bash
  export AUTH_GITHUB_CLIENT_ID=x
  export AUTH_GITHUB_CLIENT_SECRET=x
  