Fixes my hasty fix for the document batch POST

Nested forms actually posts numerically indexed hashes, rather than
arrays. Tests updated to reflect this. Original code was working!

app/models/document_batch.rb

@@ -46,7 +46,7 @@ def common_attributes
 
   def documents_attributes=(attributes)
     @documents ||= []
-    attributes.each do |document_params|
+    attributes.each do |_, document_params|
       destroy = ActiveRecord::ConnectionAdapters::Column.value_to_boolean(document_params.delete(:_destroy))
       @documents.push(Document.new(common_attributes.merge(document_params))) unless destroy
     end

spec/controllers/admin/document_batches_controller_spec.rb

@@ -27,23 +27,40 @@
       {
         'type' => 'Document::Proposal',
         filename: Rack::Test::UploadedFile.new(File.join(Rails.root, 'spec', 'support', 'annual_report_upload_exporter.csv')),
+        number: 1,
         _destroy: false
       }
     }
 
     context "when no event" do
       let(:document){ create(:document) }
 
+      it "creates a new Document" do
+        expect {
+          post :create, document_batch: {
+            date: Date.today, documents_attributes: { "0" => document_attrs }
+          }
+        }.to change(Document, :count).by(1)
+      end
+
       it "redirects to index when successful" do
         post :create, document_batch: {
-          date: Date.today, documents_attributes: [ document_attrs ]
+          date: Date.today, documents_attributes: { "0" => document_attrs }
         }
         response.should redirect_to(admin_documents_url)
       end
 
+      it "does not create a new Document" do
+        expect {
+          post :create, document_batch: {
+            date: nil, documents_attributes: { "0" => document_attrs }
+          }
+        }.to change(Document, :count).by(0)
+      end
+
       it "renders new when not successful" do
         post :create, document_batch: {
-          date: nil, documents_attributes: [ document_attrs ]
+          date: nil, documents_attributes: { "0" => document_attrs }
         }
         response.should render_template('new')
       end
@@ -54,14 +71,14 @@
 
       it "redirects to index when successful" do
         post :create, event_id: event.id, document_batch: {
-          date: Date.today, documents_attributes: [ document_attrs ]
+          date: Date.today, documents_attributes: { "0" => document_attrs }
         }
         response.should redirect_to(admin_event_documents_url(event))
       end
 
       it "renders new when not successful" do
         post :create, event_id: event.id, document_batch: {
-          date: nil, documents_attributes: [document_attrs]
+          date: nil, documents_attributes: { "0" => document_attrs }
         }
         response.should render_template('new')
       end