add router-dom

frontend/package.json

@@ -6,6 +6,7 @@
     "react": "^17.0.2",
     "react-dom": "^17.0.2",
     "react-scripts": "4.0.3",
+    "react-router-dom": "^5.2.0",
     "axios": "^0.21.1"
   },
   "scripts": {