TZInfo is a Ruby library that uses the standard tz database
(http://www.twinsun.com/tz/tz-link.htm) to provide daylight savings
aware transformations between times in different time zones.  The
tz database is compiled into Ruby classes which are packaged in the
release.  No external zoneinfo files are required at runtime.

WWW: https://github.com/tzinfo/tzinfo