Ensure file handles are closed using with statement

Author: svisser

setup.py

@@ -21,8 +21,11 @@
     print("  git push --tags")
     sys.exit()
 
-readme = open('README.rst').read()
-history = open('HISTORY.rst').read().replace('.. :changelog:', '')
+with open('README.rst') as readme_file:
+    readme = readme_file.read()
+
+with open('HISTORY.rst') as history_file:
+    history = history_file.read().replace('.. :changelog:', '')
 
 setup(
     name='django-bootstrap3',