🏗️(docs) init architecture documentation

Author: olaurendeau

README.md

@@ -13,6 +13,10 @@ Impress is built on top of [Django Rest Framework](https://www.django-rest-frame
 
 ## Getting started
 
+### Architecture
+
+Have a look at the [architecture](./docs/architecture.md) to get an overview of the project.
+
 ### Prerequisite
 
 Make sure you have a recent version of Docker and [Docker

docs/architecture.md

@@ -0,0 +1,16 @@
+## Architecture
+
+### Global system architecture
+
+```mermaid
+flowchart TD
+    User -- HTTP --> Front("Frontend (NextJS SPA)")
+    Front -- REST API --> Back("Backend (Django)")
+    Front <-- WebSocket --> Yserver("Microservice Yjs (Express)")
+    Front -- OIDC --> Back -- OIDC ---> Keycloak
+    Back -- REST API --> Yserver
+    Back --> DB("Database (PostgreSQL)")
+    Back <--> Celery --> DB
+    Back ----> S3("Minio (S3)")
+    Keycloak -- OIDC --> ProConnect
+```