Google authentication method
To be able to allow users to sign up and sign in using their Google account, you will need to get an API key from Google. First, you will need to create a new project in the Google Developers Console. You may do so at the following URL:
Once created, click on the "Credentials" menu link and then on the "OAuth consent screen" link at the top of the page.
Save the change and navigate to the "Credentials" link at the top of the page and then click on "Create credentials" and select "Oauth client ID" in the drop-down box.
Once saved, you will be shown a Client ID and Secret key. Copy these to your Google authentication page in your site's control panel.