Updated readme links

The two readme links are dead. 
1. Joshua's blog has been moved - I think I've found its new resting place.
2. The opscode docs seem to be in constant flux - I think you wanted chef10 version that referenced Joshua's blog. However possibly you wanted, [Chef 11 though that has turned data-bags into a one page topic.] (http://docs.opscode.com/chef/essentials_data_bags.html)