http://docs.ruby-lang.org/ja/1.8.7/method/Date/s/parse.html
変更前
a1=ParseDate.parsedate(from_data) a2=ParseDate.parsedate(to_data) a1b=Date::new(a1[0],a1[1],a1[2]) a2b=Date::new(a2[0],a2[1],a2[2])
変更後
a1b=Date.parse(from_data) a2b=Date.parse(to_data)