Add info about LambdaConf 2018 workshop and contributing

Author: fizruk

README.md

@@ -1,2 +1,18 @@
 # telegram-bot-simple
+
 Easy to use library for building Telegram bots in Haskell.
+
+_**Disclaimer:** this library is under development.
+It is usable for most stuff, but is still far from a stable release._
+
+## LambdaConf 2018 workshop
+
+This library was featured in a [LambdaConf 2018 workshop](https://lambdaconf2018.dryfta.com/en/program-schedule/program/32/building-a-telegram-bot-in-haskell).
+The supplementary materials for the workshop is available at https://github.com/fizruk/lambdaconf-2018-workshop.
+
+## Contributing
+
+Contributions are welcome!
+Feel free to ping me on GitHub, file an issue or submit a PR :)
+
+_Nick_