add contributing guide

Author: GarPit

CONTRIBUTING.md

@@ -0,0 +1,6 @@
+This is really easy:
+
+- [x] Fork it
+- [x] Code it
+- [x] Submit Pull Request
+- [x] Get it merged

README.md

@@ -32,3 +32,7 @@ This extension adds "Models" section in [KMS](https://github.com/webgradus/kms)
 Please watch this video to start using KMS Models:
 
 [![Getting started with KMS Models extension](http://img.youtube.com/vi/WPZoWyd-thE/0.jpg)](https://youtu.be/_INzPDZimsA "Getting started with KMS Models extension")
+
+## Contributing
+
+Please follow [CONTRIBUTING.md](CONTRIBUTING.md).