Datamapper DataMapper

When I used dm-migration to change column type on MySQL, I got SQL error and could not migrate. It seems that a SQL statement for alter column in TableModifier cause error on MySQL.
http://github.com/datamapper/dm-migrations/blob/master/lib/dm-migra...

Following code reproduce problem.

require "dm-core"
require "dm-migrations/migration_runner"

DataMapper.setup(:default, "mysql://dmtest:test@127.0.0.1/dm_test")
DataMapper::Logger.new(STDOUT, :debug)

DataMapper.logger.debug( "Starting Migration" )

migration 1, :create_people_table do
  up do
    create_table :people do
      column :id,   Integer, :serial => true
      column :name, String, :size => 50
      column :age,  Integer
    end
  end
  down do
    drop_table :people
  end
end

migration 2, :modify_people_column do
  up do
    modify_table :people do
      change_column :name, String, :size => 100
    end
  end
  down do
    modify_table :people do
      change_column :name, String, :size => 50
    end
  end
end

migrate_up!

When I run the code, I got these outputs:

== Performing Up Migration [#2](/projects/20609/tickets/2 "Ticket #2"): modify_people_column
   ALTER TABLE `people` ALTER COLUMN `name` TYPE String
    ~ You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'TYPE String' at line 1 (code: 1064, sql state: 42000, query: ALTER TABLE `people` ALTER COLUMN `name` TYPE String, uri: mysql://dmtest:test@127.0.0.1/dm_test)
    /Library/Ruby/Gems/1.8/gems/dm-core-0.10.2/lib/dm-core/adapters/data_objects_adapter.rb:61:in `execute_non_query': You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'TYPE String' at line 1 (DataObjects::SQLError)