Fix node-sass dep vuln

package.json

@@ -5,6 +5,7 @@
   "author": "",
   "private": true,
   "scripts": {
+    "dev": "./node_modules/vuepress/bin/vuepress.js dev",
     "start": "./node_modules/vuepress/bin/vuepress.js build && node server.js"
   },
   "license": "ISC",
@@ -17,7 +18,6 @@
     "express": "^4.16.3",
     "heroku-ssl-redirect": "0.0.4",
     "highlight.js": "^9.12.0",
-    "node-sass": "^4.8.3",
     "redis": "^2.8.0",
     "request": "^2.85.0",
     "sass-loader": "^7.0.1",
@@ -27,6 +27,6 @@
     "vue-images-loaded": "^1.1.2",
     "vue-moment": "^3.2.0",
     "vue-resource": "^1.5.0",
-    "vuepress": "^0.8.3"
+    "vuepress": "0.9.0"
   }
 }