[mutter] Update Compositor stage and hardware relationships

[Jonas Ådahl <jadahl src gnome org>]

commit a1b2b35c273202a26d950c569107ad7ce7342f22
Author: Jonas Ådahl <jadahl gmail com>
Date:   Sun Oct 11 13:21:41 2020 +0000

    Update Compositor stage and hardware relationships

 Compositor-stage-and-hardware-relationships.md | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
---
diff --git a/Compositor-stage-and-hardware-relationships.md b/Compositor-stage-and-hardware-relationships.md
index cfee96e..aa51ffa 100644
--- a/Compositor-stage-and-hardware-relationships.md
+++ b/Compositor-stage-and-hardware-relationships.md
@@ -1,3 +1,22 @@
+Entity relationship diagram:
+
+```mermaid
+erDiagram
+  MetaBackend ||--|| MetaMonitorManager : owns
+  MetaBackend ||--|{ MetaGpu : owns
+  MetaBackend ||--|| ClutterStage : owns
+  MetaGpu ||--|{ MetaCrtc : owns
+  MetaGpu ||--|{ MetaOutput : owns
+  MetaCrtc |o..o{ MetaOutput : assigned
+  MetaMonitorManager ||--|{ MetaMonitor : owns
+  MetaMonitorManager ||--|{ MetaLogicalMonitor : owns
+  MetaLogicalMonitor ||..|{ MetaMonitor : has
+  MetaMonitor ||..|{ MetaOutput : has
+  ClutterStage ||--|{ ClutterStageView : has
+  ClutterStageView ||..|| MetaCrtc : corresponds
+  ClutterStageView ||--|| ClutterFrameClock : owns
+```
+
 `MetaBackend`, `MetaGpu` and `MetaMonitorManager` class diagrams.
 
 ```mermaid