diff --git a/README.md b/README.md
index b890bc9eb2c3731705956d05ff6a428b273ea772..76d1ab6a36060528e951397795b3e0a6d939c512 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,9 @@ Il utilise pour ça sa propre méthode « notifyObservers() ».
 classDiagram
   class Subject
   <<Abstract>> Subject
+  Subject "1" --> "*" Observer
+  Subject : +attach(Observer)
+  Subject : +detach(Observer)
   class Observer
   <<interface>> Observer
 ```