Update README.md - add dependecies badge

Hi,

I made site for viewing status of Clojure project dependencies - http://jarkeeper.com/jamesmacaulay/shopify-clj.

Basically this pull request adds badge with the status of the dependencies in shopify-clj. It's quite useful for people who search for library to use. They can see if the project is well maintained.


What is your opinion about it?