diff --git a/README.md b/README.md
index 3b3af3f..9310823 100644
--- a/README.md
+++ b/README.md
@@ -13,12 +13,11 @@ Please refer to [Surakarta (game)](https://en.wikipedia.org/wiki/Surakarta_(game
 ## Tips of installation
 * [Node.js](https://nodejs.org/en/download/package-manager/) and [MongoDB](https://docs.mongodb.com/manual/administration/install-community/) should be installed in advance. 
 * HTTP server runs on port `2100` by default. You may change it in `bin/www`([here](/bin/www#L36)).
-* In order to display flag icons correctly, a symlink should be created manually from `node_modules/flag-icon-css` to `public/flag`. 
-* Please replace the API key of [Google Maps](https://developers.google.com/maps/documentation/javascript/tutorial) with your own key in `views/stat/map.pug`.
 * [Google reCAPTCHA](https://developers.google.com/recaptcha/docs/invisible) is integrated in this software. Please create a new file as `static_data/recaptcha.json` with following content: 
   ```json
   {"PublicKey": "[YOUR PUBLIC KEY]", "Secret": "[YOUR SECRET KEY]"}
   ```
+* Please replace the API key of [Google Maps](https://developers.google.com/maps/documentation/javascript/tutorial) with your own key in `views/stat/map.pug`.
 * Please replace the value of `global.DOMAIN_ROOT` with your own hostname in `app.js` ([here](/app.js#L39)). This global constant is to prevent the abuse of the private APIs.
 
 ## Roadmap of future development
diff --git a/package.json b/package.json
index 0a2e3f3..9552b50 100644
--- a/package.json
+++ b/package.json
@@ -2,13 +2,14 @@
   "name": "surakarta-online",
   "version": "0.2.0",
   "author": "CrabAss",
-  "license": "GPL-3.0-or-later",
+  "license": "AGPL-3.0-or-later",
   "homepage": "https://github.com/CrabAss/Surakarta-Online#readme",
   "bugs": { 
     "url" : "https://github.com/CrabAss/Surakarta-Online/issues"
   },
   "scripts": {
-    "start": "node ./bin/www"
+    "start": "node ./bin/www",
+    "postinstall": "ln -s node_modules/flag-icon-css public/flag"
   },
   "dependencies": {
     "bcrypt": "^3.0.0",