Added Django to the required packages.

Author: felixxm

setup.py

@@ -46,6 +46,7 @@
         'coreapi>=2.3.0',
         'openapi-codec>=1.3.1',
         'djangorestframework>=3.5.4',
+        'Django>=1.8',
         'simplejson'
     ],
     packages=['rest_framework_swagger'],
@@ -64,6 +65,7 @@
         'Framework :: Django :: 1.9',
         'Framework :: Django :: 1.10',
         'Framework :: Django :: 1.11',
+        'Framework :: Django :: 2.0',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: BSD License',
         'Operating System :: OS Independent',