rake db:migrate:rerun VERSION=123

rerun_migrations.rb

namespace :db do
  namespace :migrate do
    desc "Re-run a migration that's already been run"
    task :rerun => [:environment, :load_config] do
      class ActiveRecord::Migrator
        def rerun
          target = migrations.detect { |m| m.version == @target_version }
          raise UnknownMigrationVersionError.new(@target_version) if target.nil?
          target.migrate(:up)
        end

        def self.rerun(*args)
          new(*args).rerun
        end
      end

      version = ENV['VERSION'] ? ENV['VERSION'].to_i : nil
      raise 'VERSION is required' unless version
      ActiveRecord::Migrator.rerun(:rerun, ActiveRecord::Migrator.migrations_paths, version)
    end
  end
end