Fix title of tut-data in sidebar.

Original pull request #69.

index.html

@@ -94,7 +94,8 @@ The Spring Data MongoDB project provides integration with the MongoDB document d
 
 ### Tutorials
 
-* [Persisting data with Spring]({{site.main_site_url}}/guides/tutorials/data)
+* [Data Access with Spring]({{site.main_site_url}}/guides/tutorials/data)
+
 
 {% endcapture %}