docs: add link to demonstration

Author: AlexanderSchultheiss

README.md

@@ -71,6 +71,11 @@ In case you are using Nix Flakes, you can skip cloning the repository as usual:
 
 Afterward, the [result](result) symlink points to the [Javadoc](result/share/github-pages/DiffDetective/docs/javadoc/index.html), the [DiffDetective jar](result/share/java/DiffDetective/DiffDetective.jar) and a simple [script](result/bin/DiffDetective) for executing a DiffDetective main class provided as argument (e.g., evaluations used in previous research, see below under 'Publications').
 
+
+## Usage Demonstration
+[![DiffDetective Demonstration](docs/yt_thumbnail.png)](https://www.youtube.com/watch?v=q6ight5EDQY)
+
+
 ## Publications
 
 ### Classifying Edits to Variability in Source Code (ESEC/FSE 2022)
@@ -145,4 +150,4 @@ DiffDetective was extended and used within bachelor's and master's theses:
 
 [documentation]: https://variantsync.github.io/DiffDetective/docs/javadoc
 [website]: https://variantsync.github.io/DiffDetective/
-[forklg]: https://github.com/guethilu/DiffDetective
+[forklg]: https://github.com/guethilu/DiffDetective