Rusic provides some Client Apps by default for all spaces. However Google imposes domain limitations on their applications. To add Google authentication to your community you must setup your own application.
Follow the instructions below to setup your own Google Client App.
1. Create a Google Application
Login to Google then go to the Google Developers Console.
You then need to enable the Contacts API and the Google+ API.
Once done select Credentials from the sidebar, then go to the OAuth consent screen tab.
Click create then copy the ID and the secret from the popup that follows.
Finally go to the OAuth consent screen tab and enter something into the Product name shown to users field before saving.
2. Configure Rusic to use this application
Login to Rusic and then go to the Client Apps Page. Before making any changes check that you are modifying the correct community, this is shown in the top-left corner next to the Rusic icon.
Click “Add your own app” on the Google application.
You should now be able to test login by going to your community home and adding
/auth/google_oauth2 to the URL.