add react-router-dom 4.1.2

Author: kmsheng

package.json

@@ -36,7 +36,7 @@
     "react": "^15.0.1",
     "react-dom": "^15.0.1",
     "react-hot-loader": "^3.0.0-beta.6",
-    "react-router": "^3.0.2",
+    "react-router-dom": "4.1.2",
     "sass-loader": "^6.0.6",
     "style-loader": "^0.13.1",
     "url-loader": "^0.5.7",