Update Readme.md: add architecture docs.

Readme.md

@@ -13,5 +13,11 @@ This is a side project and it's still work in progress, therefore the lack of do
 
 ## Architecture
 
-TODO
+Example deployment architecture which uses [Prometheus](https://prometheus.io/) & [Grafana](https://grafana.com/) for monitoring, [Auth0](https://auth0.com/) as a authorization server
+and [Sentry](https://sentry.io/welcome/) for error reporting.
 
+![Example deployment architecture](./docs/deploy_architecture.png)
+
+The application code is organized using the [Clean Architecture](https://docs.microsoft.com/en-us/dotnet/architecture/modern-web-apps-azure/common-web-application-architectures#clean-architecture) approach.
+
+![Example deployment architecture](./docs/app_architecture_layers.png)