Add demo video for Elegant Git usage

Author: extsoft

README.md

@@ -17,8 +17,10 @@
 # Elegant Git
 Elegant Git is an assistant who carefully makes routine work with Git.
 
-Please visit <https://elegant-git.bees-hive.org/> to get started with user documentation or continue
-reading to get the project's development details.
+Please visit <https://elegant-git.bees-hive.org/> to get started with user documentation or
+click on the picture :point_down::point_down::point_down: to see a demo.
+
+[![Elegant Git Demo](docs/git-elegant-demo.png)](http://www.youtube.com/watch?v=Py6bpwJw30I)
 
 ---
 

docs/git-elegant-demo.png

@@ -12,6 +12,10 @@ Used philosophy
 > _Sounds interesting? Go to [getting started](getting-started.md) guide or take a look for
 available [commands](commands.md)._
 
+<center><iframe width="560" height="315" src="https://www.youtube.com/embed/Py6bpwJw30I"
+frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope;
+picture-in-picture" allowfullscreen></iframe></center>
+
 Elegant Git encourages using of
 [GitHub flow](https://guides.github.com/introduction/flow/). However, you can try to apply it to
 your branching strategy as well.

docs/index.md

@@ -22,6 +22,7 @@ pipeline() {
     mkdocs build --clean --strict                     || fail "Unable to build the documentation."
     pdd --exclude=.idea/**/* \
         --exclude=site/**/* \
+        --exclude=docs/*.png \
         --verbose --file=/dev/null                    || fail "Unreadable todo is identified."
     (
         ./.wf/docs-generation.bash