With a little bit of programming, your site made by Docusaurus can be modified to be accessible only to users signed in to Google.
The source material came from this article by Thomasdevshare. His article describes a similar authentication scheme for Docusaurus with Firebase as the identity provider whereas this article describes the same approach using Google API directly.
I rely heavily on Google AppEngine which is a platform-as-a-service (PaaS) offering that I can deploy my apps on without having to worry about the actual server instances powering the application.
Contrast this to infrastructure-as-a-service (IaaS) where I decide on the number of servers to spin up for my application.
The benefit of a PaaS offering is an abstraction of the underlying server stuff (and all the nitty gritty server admin issues).
This is great for the developer because the weight of the server admin hat that you have to wear is made a lot more manageable. The tradeoff for this abstraction is the lock-in that you have to endure as a developer.
This article will explain in a prescriptive manner how to use the Google Cloud Messaging service as a mechanism for performing real-time interactions for your Chrome app or extension.