Added demo

Author: turian

README.md

@@ -13,6 +13,10 @@
   <a href="https://opensource.org/licenses/Apache-2.0"><img src="https://img.shields.io/badge/License-Apache_2.0-blue.svg" alt="License"></a>
 </p>
 
+<p align="left">
+  <img src="assets/demo.mp4" alt="Demo" width="400">
+</p>
+
 ---
 
 ## Installation