Update README.md

README.md

@@ -71,6 +71,8 @@ This is a remake of [BresserWeatherSensorTTN](https://github.com/matthias-bs/Bre
   * [Default Configuration](#default-configuration)
   * [Config Helper](#config-helper)
 * [Customizing the Application Layer](#customizing-the-application-layer)
+* [Implementation](#implementation)
+  * [Class Diagram](#class-diagram)
 * [Doxygen Generated Source Code Documentation](#doxygen-generated-source-code-documentation)
 * [References](#references)
 * [Legal](#legal)
@@ -571,6 +573,12 @@ By replacing the Application Layer with your own code, you can use this project
 
 Use [extras/customization/AppLayerMinimal.h](extras/customization/AppLayerMinimal.h) and [extras/customization/AppLayerMinimal.cpp](extras/customization/AppLayerMinimal.cpp) as a template.
 
+## Implementation
+
+### Class Diagram
+
+[Class Diagram](https://www.mermaidchart.com/raw/c78b97b9-ecd9-4fc6-a6fc-bba82e0facd7?theme=light&version=v0.1&format=svg)
+
 ## Doxygen Generated Source Code Documentation
 
 [https://matthias-bs.github.io/BresserWeatherSensorWL/index.html](https://matthias-bs.github.io/BresserWeatherSensorLW/)