毎回忘れるのでメモ
# == Booting process
#
# The application is also responsible for setting up and executing the booting
# process. From the moment you require "config/application.rb" in your app,
# the booting process goes like this:
#
# 1) require "config/boot.rb" to set up load paths
# 2) require railties and engines
# 3) Define Rails.application as "class MyApp::Application < Rails::Application"
# 4) Run config.before_configuration callbacks
# 5) Load config/environments/ENV.rb
# 6) Run config.before_initialize callbacks
# 7) Run Railtie#initializer defined by railties, engines and application.
# One by one, each engine sets up its load paths, routes and runs its config/initializers/* files.
# 8) Custom Railtie#initializers added by railties, engines and applications are executed
# 9) Build the middleware stack and run to_prepare callbacks
# 10) Run config.before_eager_load and eager_load! if eager_load is true
# 11) Run config.after_initialize callbacks
特に environments と initializers について
config/environments/ENV.rb -> initializers の順