App.less -> App.sass

Author: kvker

package.json

@@ -29,6 +29,7 @@
     "html-webpack-plugin": "^3.0.6",
     "less": "^2.3.1",
     "less-loader": "^4.0.6",
+    "node-sass": "^4.9.0",
     "pug": "^2.0.1",
     "pug-loader": "^2.3.0",
     "sass": "^1.5.1",