:order - Set to an array containing :day, :month and :year to customize
the
order in which the select fields are shown. If you leave out any of the
symbols, the respective select will not be shown (like when you set
:discard_xxx
=> true. Defaults to the order defined in the respective locale (e.g.
[:year, :month, :day] in the en locale that ships with
Railshttp://api.rubyonrails.org/classes/Rails.html)
:date_separator - Specifies a string to separate the date fields.
Default
is “” (i.e. nothing).