Add the melpa badge in README

This should let people know that this package is available in melpa.

Author: tejasbubane

README.md

@@ -1,4 +1,7 @@
 # add-node-modules-path
+
+[![MELPA](http://melpa.org/packages/add-node-modules-path-badge.svg)](http://melpa.org/#/add-node-modules-path)
+
 This file provides `add-node-modules-path`, which searches
 the current files parent directories for the `node_modules/.bin/` directory
 and adds it to the buffer local `exec-path`.