Add link to Chrome web store

Author: justinfagnani

README.md

@@ -3,6 +3,12 @@
 polydev is the Polymer DevTools Extension - a tool to help develop Polymer and
 custom elements.
 
+## Release Installation
+
+The release version of polydev is available on the Chrome Web Store:
+
+https://chrome.google.com/webstore/detail/polymer-devtools-extensio/mmpfaamodhhlbadloaibpocmcomledcg
+
 ## Development
 
 ### Building
@@ -30,7 +36,9 @@ When changing files in src/ the dev workflow should work cover most use cases.
 
     > npm run dev
 
-Depending on the change you can either then close and reopen the devtools, or if you've made a change to the content-script or to element-zones, you must reload both the extension and any page you're testing it on.
+Depending on the change you can either then close and reopen the devtools, or if
+you've made a change to the content-script or to element-zones, you must reload
+both the extension and any page you're testing it on.
 
 ### Working on element-zones