chore: integrate architecture diagram

Author: Philipp Bolte

README.md

@@ -23,6 +23,11 @@ This repository includes a well-tested reference implementation that implements
 
 ## Concepts
 
+<div align="center">
+    <img src="img/registry-architecture.jpg"/>
+</div>
+
+<div align="center">
 
 ### Namespace
 
@@ -133,4 +138,4 @@ If this happens, a new contract file should be used with the changes you intend
 
 #### Contract Types
 The contract types version will follow the contract's version accordingly, but will only carry the
-major version in their name (V1, V2).
+major version in their name (V1, V2).