config/boot.rb
require 'rubygems'
# Set up gems listed in the Gemfile.
ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __dir__)
require 'bundler/setup' if File.exist?(ENV['BUNDLE_GEMFILE'])
# add the lib dir of the engine if we are running as a dummy app for an engine
$LOAD_PATH.unshift(File.expand_path('../../../lib', __dir__)) if defined?(ENGINE_ROOT)
require 'bootsnap/setup' # Speed up boot time by caching expensive operations.