Add "Leveling Up" link

redux-tutorials.md

@@ -51,3 +51,7 @@
   http://www.theodo.fr/blog/2016/03/getting-started-with-react-redux-and-immutable-a-test-driven-tutorial-part-1/  
   http://www.theodo.fr/blog/2016/03/getting-started-with-react-redux-and-immutable-a-test-driven-tutorial-part-2/  
   Another solid, in-depth tutorial, similar to the "Full-Stack" tutorial.  Builds a client-only TodoMVC app, and demonstrates a good project setup (including a Mocha+JSDOM-based testing configuration).  Well-written, covers many concepts, and very easy to follow.
+
+- **Leveling Up with React: Redux**  
+  https://css-tricks.com/learning-react-redux/  
+  A very well-written introduction to Redux and its related concepts, with some nifty cartoon-ish diagrams.