Store timestamp value as UTC
Store timestamp value as UTC

CAUTION: This is backward incompatible change. If you are using
timestamp column with no UTC timezone, you need to recreate your
database.

naoa/mroonga,mroonga/mroonga,naoa/mroonga,mroonga/mroonga,yoku0825/mroonga,yoku0825/mroonga,naoa/mroonga,mroonga/mroonga,naoa/mroonga,naoa/mroonga,naoa/mroonga,yoku0825/mroonga,yoku0825/mroonga,yoku0825/mroonga,yoku0825/mroonga,mroonga/mroonga