Add long description for Python Package Index

setup.py

@@ -1,5 +1,8 @@
 from setuptools import setup
 
+with open('README.md', 'r') as f:
+    long_description = f.read()
+
 setup(
     name='scaling',
     version='0.2.0',
@@ -7,5 +10,5 @@ setup(
     install_requires=['pint'],
     author='Dan Howe',
     author_email='d.howe@wrl.unsw.edu.au',
-    url='https://github.com/onewhaleid/scaling'
+    url='https://github.com/onewhaleid/scaling',
     description='convert units using Froude and Reynolds similitude')