days = DateTime::ABBR_DAYNAMES
# => ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
DateTime.current.wday
# => 1
days.rotate(DateTime.current.wday)
# => ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
days = DateTime::ABBR_DAYNAMES
# => ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
DateTime.current.wday
# => 1
days.rotate(DateTime.current.wday)
# => ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]