Ruby CSV
gem - smarter csv
https://github.com/tilo/smarter_csv
invalid byte sequence in UTF-8
rubyエンコーディングに詳しいblog http://tmtms.hatenablog.com/entry/20120812/ruby_encoding
encoding bug関連コメント http://blog.livedoor.jp/sonots/archives/23652294.html
from Shift_JIS to UTF-8
http://d.hatena.ne.jp/temita/20130530/1369921154