Minor changes

setup.py

@@ -5,10 +5,34 @@ Flask-Discord
 An Discord OAuth2 flask extension.
 """
 
+import re
+import os
 
 from setuptools import setup
 
 
+def __get_version():
+    with open("image_processor_client/__init__.py") as package_init_file:
+        return re.search(r'^__version__\s*=\s*[\'"]([^\'"]*)[\'"]', package_init_file.read(), re.MULTILINE).group(1)
+
+
+requirements = [
+        'Flask',
+        'requests_oauthlib',
+    ]
+
+
+on_rtd = os.getenv('READTHEDOCS') == 'True'
+if on_rtd:
+    requirements.append('sphinxcontrib-napoleon')
+
+extra_requirements = {
+    'docs': [
+        'sphinx==1.8.3'
+    ]
+}
+
+
 setup(
     name='Flask-Discord',
     version='0.0.1',
@@ -22,10 +46,8 @@ setup(
     zip_safe=False,
     include_package_data=True,
     platforms='any',
-    install_requires=[
-        'Flask',
-        'requests_oauthlib',
-    ],
+    install_requires=requirements,
+    extra_requirements=extra_requirements,
     classifiers=[
         'Environment :: Web Environment',
         'Intended Audience :: Developers',