Use ActiveRecord Column#type_cast to properly parse fields represented by a string.

Fixed issued reported by Nick Burdick where imported datetime fields was not correctly working with certain string formats for MySQL which doesn't support MM/DD/YYYY format directly.

lib/activerecord-import/adapters/abstract_adapter.rb

@@ -129,7 +129,8 @@ module ActiveRecord::Import::AbstractAdapter
       array_of_attributes.each do |arr|
         my_values = []
         arr.each_with_index do |val,j|
-          my_values << quote( val, columns[j] )
+          importable_value = columns[j].type_cast(val)
+          my_values << quote(importable_value, columns[j] )
         end
         values << my_values
       end   

lib/activerecord-import/import.rb

@@ -257,7 +257,7 @@ class ActiveRecord::Base
     def import_without_validations_or_callbacks( column_names, array_of_attributes, options={} )
       escaped_column_names = quote_column_names( column_names )
       columns = []
-      array_of_attributes.first.each_with_index { |arr,i| columns << columns_hash[ column_names[i] ] }
+      array_of_attributes.first.each_with_index { |arr,i| columns << columns_hash[ column_names[i].to_s ] }
       
       if not supports_import?
         columns_sql = "(" + escaped_column_names.join( ',' ) + ")"

test/import_test.rb

@@ -199,4 +199,16 @@ describe "#import" do
     end
   end
 
+  context "importing a datetime field" do
+    it "should import a date with MM/DD/YYYY format just fine" do
+      Topic.import [:author_name, :title, :last_read], [["Bob Jones", "Topic 1", "05/14/2010"]]
+      assert_equal "05/14/2010".to_date, Topic.last.last_read.to_date
+    end
+
+    it "should import a date with YYYY/MM/DD format just fine" do
+      Topic.import [:author_name, :title, :last_read], [["Bob Jones", "Topic 2", "2010/05/14"]]
+      assert_equal "05/14/2010".to_date, Topic.last.last_read.to_date
+    end
+  end
+
 end