re-add missing build depedencies

package.json

@@ -51,6 +51,7 @@
     "marked": "0.3.18",
     "mini-css-extract-plugin": "0.9.0",
     "moment": "2.22.1",
+    "node-sass": "4",
     "optimize-css-assets-webpack-plugin": "5.0.3",
     "pnp-webpack-plugin": "1.6.4",
     "postcss-flexbugs-fixes": "4.1.0",
@@ -61,9 +62,11 @@
     "query-string": "^6.13.1",
     "react": "^16.13.1",
     "react-dev-utils": "^10.2.1",
+    "react-dom": "^16.0.0",
     "react-router-dom": "^5.2.0",
     "resolve": "1.15.0",
     "resolve-url-loader": "3.1.2",
+    "sass-loader": "8.0.2",
     "style-loader": "0.23.1",
     "terser-webpack-plugin": "2.3.8",
     "ts-pnp": "1.1.6",