search for googleemail in user db and login as user
##Dependencies google/apiclient
composer require google/apiclient:^2.0
create an api key with the google API-Manager -https://console.developers.google.com/ register http:://yourdomain.com/check-google-login to allowed redirect urls of your app (only public domains are allowed by google)
download the oauth-credentials.json and copy it to /system/config