Fix links

Akuli · Akuli · commit 979d5dd5e333 · 2016-08-08T18:08:58.000+03:00
diff --git a/README.md b/README.md
@@ -26,9 +26,9 @@ it.**
 1. [Quick introduction to this tutorial](introduction.md)
 2. [Installing Python](installing-python.md)
 3. [Getting started with Python](getting-started.md)
-4. [ThinkPython: The way of the program](the-way-of-the-program)
+4. [ThinkPython: The way of the program](the-way-of-the-program.md)
 5. [Variables, Booleans and None](2.md)
-6. [Using functions and storing code in files](3.md)
+6. [Using functions and storing code in files](using-functions.md)
 7. [If, elif, else and while](4.md)
 
 Other things this tutorial comes with:
