Update README and add architecture diagram

Author: woop

README.md

@@ -1 +1,13 @@
-Feast Java components
+# Feast Java components
+
+## Overview
+
+This repository contains the following Feast components
+* Feast Core: The central feature registry used to define and manage entities and features
+* Feast Serving: A service used to serve the latest feature values to models
+* Feast Java SDK: A client used to retrieve features from Feast Serving
+* Helm Charts: The repository also contains Helm charts to deploy Feast Core and Feast Serving into a Kubernetes cluster
+
+# Architecture
+
+![](docs/architecture.png)