safe database cleaner strategy

database_cleaner.rb

RSpec.configure do |config|
  config.use_transactional_fixtures = false

  config.before :suite do
    DatabaseCleaner.strategy = :truncation
    DatabaseCleaner.clean_with(:truncation)
  end

  config.before(:each) do
    DatabaseCleaner.start
  end

  config.after(:each) do
    DatabaseCleaner.clean
  end
end