Add custom_arrows config functionality

lib/ransack/configuration.rb

@@ -9,7 +9,9 @@ module Ransack
     self.options = {
       :search_key => :q,
       :ignore_unknown_conditions => true,
-      :hide_sort_order_indicators => false
+      :hide_sort_order_indicators => false,
+      :up_arrow => '▼'.freeze,
+      :down_arrow => '▲'.freeze
     }
 
     def configure
@@ -75,6 +77,24 @@ module Ransack
       self.options[:ignore_unknown_conditions] = boolean
     end
 
+    # Ransack's default arrows are html-code snippets found options at the
+    # top of this file. Arrows may be anything wrapped in quotation marks.
+    # Both arrows or a single arrow may be globally overridden in an
+    # initializer file like `config/initializers/ransack.rb` as follows:
+    #
+    # Ransack.configure do |config|
+    #   # Set the up_arrow as an icon, set the down arrow as unicode
+    #   config.custom_arrows = {
+    #     up_arrow: '<i class="fa fa-long-arrow-up"></i>',
+    #     down_arrow: 'U+02193'
+    #   }
+    # end
+    #
+    def custom_arrows=(opts = {})
+      self.options[:up_arrow] = opts[:up_arrow].freeze if opts[:up_arrow]
+      self.options[:down_arrow] = opts[:down_arrow].freeze if opts[:down_arrow]
+    end
+
     # By default, Ransack displays sort order indicator arrows in sort links.
     # The default may be globally overridden in an initializer file like
     # `config/initializers/ransack.rb` as follows:

lib/ransack/helpers/form_helper.rb

@@ -110,11 +110,11 @@ module Ransack
         end
 
         def up_arrow
-          '▼'.freeze
+          Ransack.options[:up_arrow]
         end
 
         def down_arrow
-          '▲'.freeze
+          Ransack.options[:down_arrow]
         end
 
         def name