Change default_options for Rails::Server

boot.rb

# Override default options for server command
# This example changes default development host to 127.0.0.1

require 'rails/commands/server'

module Rails
  class Server
    new_defaults = Module.new do
      def default_options
        environment = ENV['RAILS_ENV'] || ENV['RACK_ENV'] || 'development'
        default_host = environment == 'development' ? '127.0.0.1' : '0.0.0.0'

        super.merge( Host: default_host )
      end
    end
 
    # Note: Module#prepend requires Ruby 2.0 or later
    prepend new_defaults
  end
end