Update index.md

Author: seankross

index.md

@@ -4,7 +4,7 @@ layout: page
 
 ## Table of Contents
 
-This is site is meant to serve as a directory for the amazing content the
+This site is meant to serve as a directory for the amazing content the
 community has created around the Data Science Specialization. If you are
 interested in contributing [click here](https://github.com/DataScienceSpecialization/DataScienceSpecialization.github.io#contributing).