- Added schematic for Trackpoint demonstration

keyboards/handwired/trackpoint/README.md

@@ -2,6 +2,9 @@
 
 This is just a simple demo to show how to integrate IBM Trackpoint in QMK.
 
+Wiring used in the demonstration:
+![Wiring example](./wiring.png)
+
 Some documentation:
 * [How to wire IBM Trackpoint](https://github.com/alonswartz/trackpoint)
 * [QMK documentation](https://docs.qmk.fm/)