Fixes awful issue where CSS on production differs from dev

The solution was upgrading vue-loader. vuejs/vue-loader#521

build/webpack.base.conf.js

@@ -3,6 +3,7 @@ const path = require('path')
 const utils = require('./utils')
 const config = require('../config')
 const vueLoaderConfig = require('./vue-loader.conf')
+const VueLoaderPlugin = require('vue-loader/lib/plugin')
 
 function resolve (dir) {
   return path.join(__dirname, '..', dir)
@@ -11,6 +12,9 @@ function resolve (dir) {
 
 
 module.exports = {
+  plugins: [
+    new VueLoaderPlugin()
+  ],
   context: path.resolve(__dirname, '../'),
   entry: {
     app: './src/main.js'

package.json

@@ -64,7 +64,7 @@
     "url-loader": "^1.1.1",
     "vue-gh-pages": "^1.19.0",
     "vue-jest": "^1.0.2",
-    "vue-loader": "^13.3.0",
+    "vue-loader": "^15.4.2",
     "vue-style-loader": "^3.0.1",
     "vue-template-compiler": "^2.5.2",
     "webpack": "^3.6.0",