make sure test database is cleaned before and after every test

spec/rails_helper.rb

@@ -1,11 +1,11 @@
 # This file is copied to spec/ when you run 'rails generate rspec:install'
-ENV['RAILS_ENV'] ||= 'test'
-require File.expand_path('../config/environment', __dir__)
+ENV["RAILS_ENV"] ||= "test"
+require File.expand_path("../config/environment", __dir__)
 # Prevent database truncation if the environment is production
-abort('The Rails environment is running in production mode!') if Rails.env.production?
-require 'spec_helper'
-require 'rspec/rails'
-Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }
+abort("The Rails environment is running in production mode!") if Rails.env.production?
+require "spec_helper"
+require "rspec/rails"
+Dir[Rails.root.join("spec/support/**/*.rb")].each { |f| require f }
 # Add additional requires below this line. Rails is not loaded until this point!
 
 # Requires supporting ruby files with custom matchers and macros, etc, in
@@ -27,6 +27,8 @@ Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }
 # If you are not using ActiveRecord, you can remove this line.
 ActiveRecord::Migration.maintain_test_schema!
 
+require "database_cleaner/active_record"
+
 RSpec.configure do |config|
   # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
   config.fixture_path = "#{::Rails.root}/spec/fixtures"
@@ -55,4 +57,22 @@ RSpec.configure do |config|
   config.filter_rails_from_backtrace!
   # arbitrary gems may also be filtered via:
   # config.filter_gems_from_backtrace("gem name")
+  # config.before(:each) do
+  #   DatabaseCleaner.strategy = :deletion
+  # end
+  # config.append_after(:each) do
+  #   DatabaseCleaner.clean
+  # end
+  config.before(:suite) do
+    DatabaseCleaner.strategy = :transaction
+    DatabaseCleaner.clean_with(:truncation)
+  end
+
+  config.before(:each) do
+    DatabaseCleaner.start
+  end
+
+  config.after(:each) do
+    DatabaseCleaner.clean
+  end
 end