add react-router-dom

Author: hafidz

client/package.json

@@ -8,6 +8,7 @@
     "hover.css": "^2.2.1",
     "react": "^16.2.0",
     "react-dom": "^16.2.0",
+    "react-router-dom": "^4.2.2",
     "react-scripts": "1.0.17"
   },
   "scripts": {