Move the `Django` section under `Python`

Django is a high-level Python Web framework, therefore, it should be
included as a subsection of `Python`.

Ref: https://www.djangoproject.com/

free-programming-books.md

@@ -18,7 +18,6 @@
 * [DTrace](#dtrace)
 * [DB2](#db2)
 * [Delphi / Pascal](#delphi--pascal)
-* [Django](#django)
 * [Elasticsearch](#elasticsearch)
 * [Emacs](#emacs)
 * [Erlang](#erlang)
@@ -62,6 +61,7 @@
 * [Prolog](#prolog)
 * [PostgreSQL](#postgresql)
 * [Python](#python)
+    * [Django](#django)
 * [R](#r)
 * [Racket](#racket)
 * [Ruby](#ruby)
@@ -372,12 +372,6 @@
 * [Essential Pascal Version 1 and 2](http://www.marcocantu.com/epascal/)
 
 
-###Django
-
-* [Djen of Django](http://agiliq.com/books/djenofdjango/)
-* [Django by Example](http://www.lightbird.net/dbe/)
-
-
 ###Elasticsearch
 
 * [Exploring Elasticsearch](http://exploringelasticsearch.com/)
@@ -741,6 +735,11 @@
 * [Snake Wrangling For Kids](http://www.briggs.net.nz/snake-wrangling-for-kids.html)
 * [Think Python](http://www.greenteapress.com/thinkpython/) - Allen B. Downey
 
+####Django
+
+* [Djen of Django](http://agiliq.com/books/djenofdjango/)
+* [Django by Example](http://www.lightbird.net/dbe/)
+
 
 ###R