發生了以下兩個錯誤：

zlib is missing; necessary for building libxml2

xslt is missing. Please locate mkmf.log to investigate how it is failing.

解決方法

• 安裝 libxslt 與 libxml2
• 指定 brew 安裝的 libxml2 路徑

brew install libxslt libxml2
bundle config build.nokogiri --use-system-libraries --with-xml2-include=$(brew --prefix libxml2)/include/libxml2

參考網站

• Don't hate nokogiri Overcoming installation errors
• nokogiri cannot be installed on macOS