[BUG]: Wrong ENV variable documented for Google Single Sign-On

[Antho331364]

Describe the bug
On the official documentation it is documented to declare the following environment variables to use the Google SSO functionality:

• LAGO_GOOGLE_AUTH_CLIENT_ID
• LAGO_GOOGLE_AUTH_CLIENT_SECRET

These variables are not the right ones to declare according to the code itself.

The following environment variables must be declared:

• GOOGLE_AUTH_CLIENT_ID
• GOOGLE_AUTH_CLIENT_SECRET

In addition to this, you also need to edit the docker-compose.yml and add the env variables to the api service block of the compose file:

 environment:
    ...
    - GOOGLE_AUTH_CLIENT_ID=${GOOGLE_AUTH_CLIENT_ID:-}
    - GOOGLE_AUTH_CLIENT_SECRET=${GOOGLE_AUTH_CLIENT_SECRET:-}

Last but not least, it's not documented currently anywhere but you need to set the Allowed redirect URIs in your Google Cloud console where you define your OAuth credentials for Lago which is the Lago front URL(with port if different than 80 or 443) followed by "/auth/google/callback". Ex: http(s)://yourdomain.com/auth/google/callback

And the Allowed JavaScript origins set to the Lago front URL(with port if different than 80 or 443). Ex : http(s)://yourdomain.com

Expected behavior
Well documented environment variables for Google SSO feature and additional instructions to update the docker-compose.yml file according to these variables, plus the allowed javascript origin and allowed redirect URIs to set.