Let npm install bower

One less step for new contributors who need to add dependencies.

README.md

@@ -28,8 +28,10 @@ You should now be able to use the extension. If you need to reset your developme
 
 Dependencies
 ============
-Dependencies are managed by [bower](bower.io). You'll need to install
-node, npm, and bower to change them.
+
+Dependencies are managed by [bower](bower.io) and built with
+[grunt](gruntjs.com). To change them, you'll need to install node and npm, then
+run `npm install` to install bower, grunt, and related plugins.
 
 ### Adding a bower component
 

package.json

@@ -6,6 +6,7 @@
     "grunt": "^0.4.5",
     "grunt-contrib-concat": "^0.5.0",
     "grunt-contrib-jshint": "~0.10.0",
-    "grunt-preen": "^1.0.0"
+    "grunt-preen": "^1.0.0",
+    "bower": "^1.3.12"
   }
 }