Add doc and example on using different bucket types 

I saw them supported in the code but not in the readme.

By the way, it is really convenient when the chef opscode community cookbook
(http://community.opscode.com/cookbooks/couchbase) links right to the git page.  I wouldn't have even known there was a git page without seeing the link in one of the community comments.  Putting it on the community homepage could increase the chances of other community pull requests.