Updated index page

Author: tisnik

docs/README.md

@@ -31,6 +31,11 @@ See the full documentation at [`../README.md`](../README.md) or browse sub-pages
 
 
 
+## Info for developers
+
+[Contributing guide](https://lightspeed-core.github.io/lightspeed-stack/CONTRIBUTING.html)
+
+
 ## API
 
 [OpenAPI specification](https://lightspeed-core.github.io/lightspeed-stack/openapi.html)