Skip mailers while generating Rails 5 app

We can now skip requiring Action Mailer while generating Rails 5 app.

$ rails new my_app --skip-action-mailer

# OR

$ rails new my_app -M

This comments out requiring action_mailer/railtie in application.rb.

It also omits mailer specific configurations such as config.action_mailer.raise_delivery_errors and config.action_mailer.perform_caching in production/development and config.action_mailer.delivery_method by default in test environment.

# application.rb

require "rails"
require "active_model/railtie"
require "active_job/railtie"
require "active_record/railtie"
require "action_controller/railtie"
# require "action_mailer/railtie"
require "action_view/railtie"
require "action_cable/engine"
require "sprockets/railtie"
require "rails/test_unit/railtie"

As, we can see action_mailer/railtie is commented out.