docs: update readme

Author: bibendi

README.md

@@ -19,6 +19,10 @@ And then execute:
 bundle install
 ```
 
+## Demo
+
+Learn how to use this gem and how it works with Ruby on Rails at here https://github.com/SberMarket-Tech/outbox-example-apps
+
 ## Auto configuration
 
 We recommend going through the configuration and file creation process using the following Rails generators. Each generator can be run by using the `--help` option to learn more about the available arguments.