docs: add event sourcing architecture diagram

event-sourcing/README.md

@@ -41,6 +41,10 @@ In plain words
 
 > The Event Sourcing pattern defines an approach to handling operations on data that's driven by a sequence of events, each of which is recorded in an append-only store. Application code sends a series of events that imperatively describe each action that has occurred on the data to the event store, where they're persisted. Each event represents a set of changes to the data (such as AddedItemToOrder).
 
+Architecture diagram
+
+![Event Sourcing Architecture Diagram](./etc/event-sourcing-architecture-diagram.png)
+
 ## Programmatic Example of Event Sourcing Pattern in Java
 
 In the programmatic example we transfer some money between bank accounts.