Hacking in bigint support for Mysql and Postgresql. Got a better method?

environment.rb

# Load the rails application
require File.expand_path('../application', __FILE__)

require 'active_record/connection_adapters/mysql2_adapter'
require 'active_record/connection_adapters/postgresql_adapter'

ActiveRecord::ConnectionAdapters::Mysql2Adapter::NATIVE_DATABASE_TYPES[:big_primary_key] = "BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY".freeze
ActiveRecord::ConnectionAdapters::PostgreSQLAdapter::NATIVE_DATABASE_TYPES[:big_primary_key] = "bigserial primary key".freeze

# Initialize the rails application
Ou1::Application.initialize!

Hi, I try this solution, but when I run rake db:migrate, Error thourghed like this

undefined method `uuid' for #<ActiveRecord::ConnectionAdapters::TableDefinition

I found rake task hasnot load the environment.rb file.

Am i do wrong?
Thx!