remove transactions stuff from Test::Unit section

... as there is a specific section about it further down.

README.md

@@ -162,36 +162,14 @@ end
 
 ## Using Capybara with Test::Unit
 
-* If you are using Rails, add `database_cleaner` to your Gemfile:
-
-    ```ruby
-    group :test do
-      gem 'database_cleaner'
-    end
-    ```
-
-    Then add the following code in your `test_helper.rb` file to make
-    Capybara available in all test cases deriving from
+* If you are using Rails, add the following code in your `test_helper.rb` 
+    file to make Capybara available in all test cases deriving from
     `ActionDispatch::IntegrationTest`:
 
     ```ruby
-    # Transactional fixtures do not work with Selenium tests, because Capybara
-    # uses a separate server thread, which the transactions would be hidden
-    # from. We hence use DatabaseCleaner to truncate our test database.
-    DatabaseCleaner.strategy = :truncation
-
     class ActionDispatch::IntegrationTest
       # Make the Capybara DSL available in all integration tests
       include Capybara::DSL
-
-      # Stop ActiveRecord from wrapping tests in transactions
-      self.use_transactional_fixtures = false
-
-      teardown do
-        DatabaseCleaner.clean       # Truncate the database
-        Capybara.reset_sessions!    # Forget the (simulated) browser state
-        Capybara.use_default_driver # Revert Capybara.current_driver to Capybara.default_driver
-      end
     end
     ```