Migrate Rails 4

gistfile1.rb

require 'active_record'
require 'foreigner'
require 'yaml'
require 'logger'
require 'pathname'

task :environment do
end

namespace :db do
  task :load_config do
    unless ActiveRecord::Tasks::DatabaseTasks.root
      environment = ENV['RACK_ENV'] || 'development'
      project_dir = Pathname.new File.join(__dir__, '..', '..')
      config_file = Pathname.new File.join(project_dir, 'config', 'settings.yml')
      config = YAML::load(config_file.open)

      ActiveRecord::Tasks::DatabaseTasks.root = project_dir
      ActiveRecord::Tasks::DatabaseTasks.migrations_paths = project_dir.join('db', 'migrations')
      ActiveRecord::Tasks::DatabaseTasks.db_dir = 'db'
      ActiveRecord::Tasks::DatabaseTasks.database_configuration = config
      ActiveRecord::Tasks::DatabaseTasks.env = environment

      ActiveRecord::Base.establish_connection ActiveRecord::Tasks::DatabaseTasks.database_configuration[environment]
      ActiveRecord::Base.logger = Logger.new STDOUT

      Foreigner.load
    end
  end
end

load "active_record/railties/databases.rake"