Add script to deploy to gh-pages

Author: jakezatecky

package.json

@@ -16,7 +16,8 @@
   "bugs": "https://github.com/jakezatecky/react-checkbox-tree/issues",
   "main": "lib/index.js",
   "scripts": {
-    "examples": "gulp examples"
+    "examples": "gulp examples",
+    "gh-deploy": "git subtree push --prefix examples/dist origin gh-pages"
   },
   "peerDependencies": {
     "react": "^15.3.0"