Let ransack know about translations

Since globalize 5 won't store translated data on default tables we need
to tweak the table / attribute name to let it fetch the data on the
right place.

This is just a proof of concept on what we could do to
improve the spree / ransack / globalize love here. Not sure this will
work with associations yet or even if it will work at all in all
scenarios

app/models/spree/globalize/translatable.rb

@@ -6,6 +6,23 @@ module Translatable
       included do
         accepts_nested_attributes_for :translations
       end
+
+      class_methods do
+        def ransack(params = {}, options = {})
+          names = params.keys
+
+          names.each do |n|
+            translated_attribute_names.each do |t|
+              if n.to_s.starts_with? t.to_s
+                params[:"translations_#{n}"] = params[n]
+                params.delete n
+              end
+            end
+          end
+
+          super(params, options)
+        end
+      end
     end
   end
 end

spec/models/product_spec.rb

@@ -19,6 +19,11 @@ module Spree
       expect(product.taxons).to include(taxon)
     end
 
+    it "handle translation in ransack" do
+      result = described_class.ransack(name_cont: product.name[0..2]).result
+      expect(result.first).to eq product
+    end
+
     # Regression tests for #466
     describe ".like_any" do
       context "allow searching products through their translations" do