Add YARD docs for Faker::Business. (faker-ruby#1852)

lib/faker/default/business.rb

@@ -7,14 +7,41 @@ class Business < Base
     flexible :business
 
     class << self
+      ##
+      # Produces a credit card number.
+      #
+      # @return [String]
+      #
+      # @example
+      #   Faker::Business.credit_card_number #=> "1228-1221-1221-1431"
+      #
+      # @faker.version 1.2.0
       def credit_card_number
         fetch('business.credit_card_numbers')
       end
 
+      ##
+      # Produces a credit card expiration date.
+      #
+      # @return [Date]
+      #
+      # @example
+      #   Faker::Business.credit_card_number #=> <Date: 2015-11-11 ((2457338j,0s,0n),+0s,2299161j)>
+      #
+      # @faker.version 1.2.0
       def credit_card_expiry_date
         ::Date.today + (365 * rand(1..4))
       end
 
+      ##
+      # Produces a type of credit card.
+      #
+      # @return [String]
+      #
+      # @example
+      #   Faker::Business.credit_card_type #=> "visa"
+      #
+      # @faker.version 1.2.0
       def credit_card_type
         fetch('business.credit_card_types')
       end