app/lib/age.rb
module Age
def self.in_years(dob, now = Date.current)
return nil if dob.blank?
# reference: http://stackoverflow.com/questions/819263/get-persons-age-in-ruby#comment21200772_819263
now.year - dob.year - (now.month > dob.month || (now.month == dob.month && now.day >= dob.day) ? 0 : 1)
end
end