setup: improve description (apache#5226)

* setup: improve description

* setup: use README.md as long_description

As pypy.io now should render markdown.

setup.py

@@ -16,6 +16,9 @@
 with open(PACKAGE_FILE) as package_file:
     version_string = json.load(package_file)['version']
 
+with open('README.md') as readme:
+    long_description = readme.read()
+
 
 def get_git_sha():
     try:
@@ -42,8 +45,8 @@ def get_git_sha():
 setup(
     name='superset',
     description=(
-        'A interactive data visualization platform build on SqlAlchemy '
-        'and druid.io'),
+        'A modern, enterprise-ready business intelligence web application'),
+    long_description=long_description,
     version=version_string,
     packages=find_packages(),
     include_package_data=True,