chore(README): add contributing section

Author: doshprompt

README.md

@@ -77,6 +77,13 @@ $ npm install -d
 $ npm test
 ```
 
+##### Contributing
+
+In lieu of a formal style guide, pleae take good care to maintain the existing coding style.
+Add unit tests for any new or changed functionality. Lint and test your code using [Grunt](http://gruntjs.com/).
+Please refer to this [document][commit-message-format] for a detailed explanation of git commit guidelines - source: [AngularJS](https://angualrjs.org)
+[commit-message-format]: https://docs.google.com/document/d/1QrDFcIiPjSLDn3EL15IJygNPiHORgU1_OOAqWjiDU5Y/edit#
+
 ## Getting Started
 
 ### Quick Start