It's time to collect stamps at the venue of #rubykaigi2023 ! - Rubyist Book Authors Stamp Rally / 最近本を出したRubyistに話しかけようスタンプラリー #rubykaigi2023 会場 をやります #authorsrb English ver.What is the Rubyist Book Authors Stamp Rally? In Japan, many Rubyist have been publishing books (off course in Japanese) recently, so we've decided to organize an event to bring together RubyKaigi participants and these author