fixed webpack devserver to serve router subpath

package.json

@@ -22,7 +22,8 @@
     "vue": "^2.6.10",
     "vue-meta": "^1.6.0",
     "vue-router": "^3.1.3",
-    "vuex": "^3.1.1"
+    "vuex": "^3.1.1",
+    "vuex-router-sync": "^5.0.0"
   },
   "devDependencies": {
     "@babel/core": "^7.6.0",
@@ -44,6 +45,7 @@
     "eslint-plugin-vue": "^5.2.3",
     "eslint-plugin-vue-a11y": "0.0.28",
     "file-loader": "^4.2.0",
+    "html-webpack-harddisk-plugin": "^1.0.1",
     "html-webpack-plugin": "^3.2.0",
     "jest": "^24.9.0",
     "jest-serializer-vue": "^2.0.2",