Add Cloud Code guide to README (#890)

Makes the guide easily accessible.

Author: dplewis

README.md

@@ -26,7 +26,7 @@
 </p>
 <br>
 
-For more information on Parse and its features, see [the website](https://parseplatform.org), [the JavaScript guide](https://docs.parseplatform.org/js/guide/) or [API Reference](https://parseplatform.org/Parse-SDK-JS/api/).
+For more information on Parse and its features, see [the website](https://parseplatform.org), [the JavaScript guide](https://docs.parseplatform.org/js/guide/), [the Cloud Code guide](https://docs.parseplatform.org/cloudcode/guide/) or [API Reference](https://parseplatform.org/Parse-SDK-JS/api/).
 
 ## Getting Started