Update requires to avoid pulling in ActiveRecord, fix other require errors

Author: petergoldstein

Rakefile

@@ -160,7 +160,7 @@ namespace :no_active_record do
         sh "rm -f #{bindir}/rails"
         sh "bundle exec rails new #{example_app_dir} --no-rc --skip-active-record --skip-javascript --skip-bootsnap " \
            "--skip-sprockets --skip-git --skip-test-unit --skip-listen --skip-bundle --skip-spring " \
-           "--template=example_app_generator/generate_app.rb"
+           "--skip-action-text --template=example_app_generator/generate_app.rb"
 
         in_example_app(app_dir: example_app_dir) do
           sh "./ci_retry_bundle_install.sh 2>&1"

example_app_generator/no_active_record/app/models/in_memory/model.rb

@@ -1,5 +1,7 @@
 raise "ActiveRecord is defined but should not be!" if defined?(::ActiveRecord)
 
+require 'active_model'
+
 module InMemory
   module Persistence
     def all

example_app_generator/spec/support/default_preview_path

@@ -28,7 +28,7 @@ require_file_stub 'config/environment' do
     require "action_view/railtie"
     if Rails::VERSION::STRING >= '6'
       require "action_cable/engine"
-      require "action_mailbox/engine"
+      require "active_job/railtie"
     end
 
     # Require the gems listed in Gemfile, including any gems