Update .gitignore.
Update .gitignore.

Signed-off-by: Masanori Ogino <c49462fef669560e618607913e6c283f7627123c@gmail.com>

omasanori/picrin,dcurrie/picrin,omasanori/picrin,picrin-scheme/picrin,picrin-scheme/picrin,dcurrie/picrin