config/initializers/new_framework_defaults.rb

# Be sure to restart your server when you modify this file.
#
# This file contains migration options to ease your Rails 5.0 upgrade.
#
# Read the Rails 5.0 release notes for more info on each option.

# Make Ruby 2.4 preserve the timezone of the receiver when calling `to_time`.
# Previous versions had false.
ActiveSupport.to_time_preserves_timezone = true

# Require `belongs_to` associations by default. Previous versions had false.
Rails.application.config.active_record.belongs_to_required_by_default = true

# Configure SSL options to enable HSTS with subdomains. Previous versions had false.
Rails.application.config.ssl_options = { hsts: { subdomains: true } }