Support for a non UTF-8 file when zip uploading (#185)

lib/active_admin_import/model.rb

@@ -110,7 +110,7 @@ def encode_file
 
     def unzip_file
       Zip::File.open(file_path) do |zip_file|
-        self.file = Tempfile.new(CONST::TMP_FILE)
+        self.file = Tempfile.new(CONST::TMP_FILE, binmode: true)
         data = zip_file.entries.select(&:file?).first.get_input_stream.read
         file << data
         file.close

spec/import_spec.rb

@@ -371,6 +371,20 @@ def upload_file!(name, ext = 'csv')
             end
           end
         end
+
+        context 'when zipped with Win1251 file' do
+          let(:options) do
+            attributes = { force_encoding: :auto }
+            { template_object: ActiveAdminImport::Model.new(attributes) }
+          end
+          it 'should import file' do
+            with_zipped_csv(:authors_win1251_win_endline) do
+              upload_file!(:authors_win1251_win_endline, :zip)
+              expect(page).to have_content 'Successfully imported 2 authors'
+              expect(Author.count).to eq(2)
+            end
+          end
+        end
       end
 
       context 'with different header attribute names' do