Add resource (#614)

Hello,

I am Saurabh, co-founder of Hackr.io. Hackr.io is a programming community & a great place to find the best online programming courses and tutorials. It's a one stop solution for tutorial recommendations with 5000+ tutorial of more than 140 programming languages.

I was looking at your learning resources page and found it pretty useful. I believe that Hackr.io would be really useful to the developer community in finding the right programming course/tutorial and would make a nice addition to your resource page.
Hackr is also listed on other esteemed websites like Lehigh University's resource page and official Official Python wiki page to name a few.

Thanks for the list of great resources you have compiled. Enjoy your week:)

Author: Saurabh-hooda

README.md

@@ -84,6 +84,7 @@ Community (college) maintained list of Algorithms and Data Structures implementa
 * [Intro to Algorithms - Khan Academy](https://www.khanacademy.org/computing/computer-science/algorithms)
 * [Popular Data Structures and Algorithms - Codechef](https://discuss.codechef.com/questions/48877/data-structures-and-algorithms)
 * [Stanford-ACM-Codes](https://github.com/jaehyunp/stanfordacm) - A list of codes written by previous Stanford ACM team members and coaches.
+* [Data Structures and Algorithms](https://hackr.io/tutorials/learn-data-structures-algorithms) - A user ranked list of online tutorials to learn Data Structures and Algorithms online.