Update README.md

Author: r-veenstra

README.md

@@ -4,6 +4,8 @@ This repository contains the starter code used in the [iTwin + Cesium Introducti
 
 Have questions? Ask them on the [community forum](https://community.cesium.com).
 
+Found a bug? Open an [issue](https://github.com/iTwin/itwin-cesium-tutorial-app/issues).
+
 ## 🚀 Using the Tutorial Starter Code (main branch)
 
 1. Clone the repository  
@@ -37,3 +39,5 @@ Have questions? Ask them on the [community forum](https://community.cesium.com).
 
 [Apache 2.0](http://www.apache.org/licenses/LICENSE-2.0.html). The iTwin + Cesium Introduction Tutorial App is free to use as starter project for both commercial and non-commercial use.
 
+## 👥Contributions
+Pull requests are appreciated. Please use the same [Contributor License Agreement (CLA)](https://github.com/CesiumGS/cesium/blob/master/CONTRIBUTING.md) used for [Cesium](https://cesium.com/).