Update instructions to include node setup for Apple Silicon laptops

mac.sh を読み、そこにある Node と nvm のセットアップを、issue に示されている Homebrew ~/.zshrc の設定と比較してください。Apple Silicon Mac でセットアップを実行するか、生成された設定を確認してください。Node の Apple Silicon 対応バージョンを手順で使用し、報告されている「source .zshrc」および「bad CPU type」エラーを回避できれば完了です。

I have a new M1 Mac and following the steps in https://github.com/fastruby/setup/blob/main/mac.sh I wasn't able to get node to work. I've used yarn in the past so I figured I was doing something wrong with nvm, but it turns out you need the latest version of node (16) for Apple Silicon support, and the script is using an older version. See here: https://www.infoworld.com/article/3615673/nodejs-16-introduces-apple-silicon-support.html

Specifically, when I updated my .zshrc file, this happened:

~ $ source .zshrc
Please see `nvm --help` or https://github.com/nvm-sh/nvm#nvmrc for more information.

So there was an error, but I couldn't tell what it was (the output from the error wasn't being shown for some reason). I tried a variety of things, but eventually figured it out with:

~ $ node -v
zsh: bad CPU type in executable: node

Also, what I ultimately put in my .zshrc file is different from what's in the mac.sh script. I used what was recommended by homebrew after installing nvm:

Add the following to ~/.zshrc or your desired shell
configuration file:

  export NVM_DIR="$HOME/.nvm"
  [ -s "/opt/homebrew/opt/nvm/nvm.sh" ] && \. "/opt/homebrew/opt/nvm/nvm.sh"  # This loads nvm
  [ -s "/opt/homebrew/opt/nvm/etc/bash_completion.d/nvm" ] && \. "/opt/homebrew/opt/nvm/etc/bash_completion.d/nvm"  # This loads nvm bash_completion