Replace in your config/application.rb
require "rails/all"with:
require "rails"
# Pick the frameworks you want:
require "active_record/railtie"
require "action_controller/railtie"
require "sprockets/rails/railtie"
require "action_mailer/railtie"
require "rails/test_unit/railtie"For example to disable sprockets-rails you can comment require "sprockets/rails/railtie".
This is done automatically for new apps when you use some of --skip-* flags, for example you can start a new app with sprockets railtie turned off with rails new foo --skip-sprockets