Remove unused module (#148)

package.json

@@ -21,7 +21,6 @@
     "express": "^4.15.2",
     "firebase": "^3.7.2",
     "lru-cache": "^4.0.2",
-    "serialize-javascript": "^1.3.0",
     "serve-favicon": "^2.4.1",
     "vue": "^2.2.4",
     "vue-router": "^2.3.0",