Registers a new date format for formatting Date instances. See Date::DATE_FORMATS for built-in formats. Use the format name as the name and either a strftime string or Proc instance that takes a date argument as the value.
Date
Date::DATE_FORMATS
Source: show | on GitHub
# File activesupport/lib/active_support/date_formats.rb, line 32 def self.register(name, format) @list = @list.merge(name => format).freeze end