freelance rails consultant. ginza.rb organizer. perfect ruby on rails author.
Co-founder of <a href='https://coderdojo.jp/'>CoderDojo Japan Association</a> & <a href='https://jr.mitou.org/'>Mitou...
Fulltime OSS developer (Crowi), Serial entrepreneur and sometimes Racer.
Former Manager, VPoE and CTO at Mercari. ...
