#120 - readme add RPA Challenge example

Author: kensoh

README.md

@@ -88,7 +88,7 @@ r.close()
 
 # API Reference
 
-Check out [sample Python script](https://github.com/tebelorg/RPA-Python/blob/master/sample.py) and [RedMart groceries example](https://github.com/tebelorg/RPA-Python/issues/24). \* If you've discovered an unknown bug when using this tool, [kindly raise a GitHub issue](https://github.com/tebelorg/RPA-Python/issues) and I'll buy you and one friend a cup of Starbucks (one each, any drink, any size, any city). I appreciate your time fiddling with a bug, trying to replicate it, and working with me to fix it. :tea::coffee:
+Check out [sample Python script](https://github.com/tebelorg/RPA-Python/blob/master/sample.py), [RPA Challenge example](https://github.com/tebelorg/RPA-Python/issues/120#issuecomment-610518196), and [RedMart groceries example](https://github.com/tebelorg/RPA-Python/issues/24). \* If you've discovered an unknown bug when using this tool, [kindly raise a GitHub issue](https://github.com/tebelorg/RPA-Python/issues) and I'll buy you and one friend a cup of Starbucks (one each, any drink, any size, any city). I appreciate your time fiddling with a bug, trying to replicate it, and working with me to fix it. :tea::coffee:
 
 #### ELEMENT IDENTIFIERS
 An element identifier helps to tell RPA for Python exactly which element on the user interface you want to interact with. For example, //\*[@id="email"] is an XPath pointing to the webpage element having the id attribute "email".