Add license to setup.py

Author: sergiuser1

setup.py

@@ -156,6 +156,7 @@ def package_files(directory):
     'author': 'Quantopian Inc.',
     'author_email': '[email protected]',
     'url': 'https://github.com/quantopian/qgrid',
+    'license': 'Apache-2.0',
     'keywords': [
         'ipython',
         'jupyter',