Add Think Python to programming readings (ossu#408)

extras/readings.md

@@ -12,6 +12,7 @@ Or, if you are struggling in one of the courses, perhaps reading a book on the s
 Name | Author(s)
 :-- | :--:
 [Introduction to Computation and Programming Using Python](https://www.amazon.com/Introduction-Computation-Programming-Using-Python/dp/0262525003/) | John V. Guttag
+[Think Python 2e](http://greenteapress.com/wp/think-python-2e/) | Allen B. Downey
 [How to Design Programs](http://www.ccs.neu.edu/home/matthias/HtDP2e/) | Matthias Felleisen, Robert Bruce Findler, Matthew Flatt, Shriram Krishnamurthi
 [Structure and Interpretation of Computer Programs](https://mitpress.mit.edu/sicp/full-text/book/book.html) | Hal Abelson, Jerry Sussman, Julie Sussman 
 [Concepts, Techniques, and Models of Computer Programming](https://www.amazon.com/gp/product/0262220695) | Peter Van Roy, Seif Haridi
@@ -65,4 +66,4 @@ Name | Author(s)
 [Language Implementation Patterns](https://www.amazon.com/gp/product/193435645X) | Terence Parr
 [Compilers: Principles, Techniques, and Tools (2nd Edition)](http://www.amazon.com/Compilers-Principles-Techniques-Tools-2nd/dp/0321486811/) | Alfred V. Aho, Monica S. Lam, Ravi Sethi,  Jeffrey D. Ullman
 [Compiler Construction](http://www.ethoberon.ethz.ch/WirthPubl/CBEAll.pdf) | Niklaus Wirth 
-[The Mythical Man-Month](https://www.amazon.com/Mythical-Man-Month-Software-Engineering-Anniversary/dp/0201835959/) | Fred Brooks, Jr.
+[The Mythical Man-Month](https://www.amazon.com/Mythical-Man-Month-Software-Engineering-Anniversary/dp/0201835959/) | Fred Brooks, Jr.