TZInfo is a Ruby library that provides daylight savings aware transformations
between times in different timezones.

TZInfo requires a source of timezone data. There are two built-in options:
- The separate TZInfo::Data library (the tzinfo-data gem). TZInfo::Data contains
  a set of Ruby modules that are generated from the IANA Time Zone Database.
- A zoneinfo directory. Most Unix-like systems include a zoneinfo directory
  containing timezone definitions. These are also generated from the IANA Time
  Zone Database.

By default, TZInfo::Data will be used. If TZInfo::Data is not available, then
TZInfo will search for a zoneinfo directory instead.

WWW: https://tzinfo.github.io/