Fix DB corruption in system tests after exceptions

This is a known bug in Rails, fixed in the Rails 5.2 and Rails 6.x
branches:

https://github.com/rails/rails/pull/32293/commits/5c4e1338

spec/rails_helper.rb

@@ -19,6 +19,18 @@ Warden.test_mode!
 
 ActiveRecord::Migration.maintain_test_schema!
 
+# Monkey patch from https://github.com/rails/rails/pull/32293
+# Remove when we upgrade to Rails 5.2
+require "action_dispatch/system_testing/test_helpers/setup_and_teardown"
+module ActionDispatch::SystemTesting::TestHelpers::SetupAndTeardown
+  def after_teardown
+    take_failed_screenshot
+    Capybara.reset_sessions!
+  ensure
+    super
+  end
+end
+
 RSpec.configure do |config|
   config.infer_spec_type_from_file_location!
   config.after do