add how to install yarn via apt for Ubuntu users.

README.md

@@ -42,34 +42,51 @@ and run a local server. This section shows you how.
 
 [Node.js](https://nodejs.org/en/download) version 16.14 or above (which can be checked by running `node -v`). You can use [nvm](https://github.com/nvm-sh/nvm) for managing multiple Node versions on a single machine installed.
 
-### Install yarn
+- apt
 
+```shell
+curl -sL https://deb.nodesource.com/setup_16.x | sudo -E bash -
+sudo apt install -y nodejs
 ```
+
+### Install yarn
+
+- npm
+
+```shell
 npm install -g yarn
 ```
 
-### Install dependencies
+- apt
 
+```shell
+curl -sL https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
+sudo apt update
+sudo apt install -y yarn
 ```
-cd website
 
+### Install dependencies
+
+```shell
+cd website
 yarn
 ```
 
 ### Local Development
 
-```
-$ yarn start
+```shell
+yarn start
 ```
 
 This command starts a local development server and opens up a browser window. Most changes are reflected live without having to restart the server.
 
-Your website is at [http://localhost:3000/](http://localhost:3000/)
+Your website is at [http://localhost:3000/](http://localhost:3000/). (You can also use `--host` option to bind the IP address instead of `localhost`.)
 
 ### Build
 
-```
-$ yarn build
+```shell
+yarn build
 ```
 
 This command generates static content into the `build` directory and can be served using any static contents hosting service.