engine.rb

require 'rails'

module Cms
  class Engine < Rails::Engine
    rake_tasks do
      load "cms/railties/tasks.rake"
    end
  end
end

tasks.rake

namespace :cms do
  desc "Run cms migrations (options: VERSION=x, VERBOSE=false)."
  task :migrate => :environment do
    ActiveRecord::Migration.verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] == "true" : true
    ActiveRecord::Migrator.migrate(File.join(File.dirname(__FILE__), "../../../db/migrate/"), ENV["VERSION"] ? ENV["VERSION"].to_i : nil)
    Rake::Task["db:schema:dump"].invoke if ActiveRecord::Base.schema_format == :ruby
  end
end