use timestamp at embulk input plugin

gistfile1.md

def self.transaction(config, &control)
  columns = [Column.new(0, 'time', :timestamp)]
end

def run
  @page_builder.add([Time.now])
end

2015-02-05 00:03:41,820 [INFO]: main:org.embulk.exec.LocalExecutor: {done:  1 / 1, running: 0}
2015-02-05 00:03:41,842 [INFO]: main:org.embulk.command.Runner: Transaction partially failed. Cleaning up the intermediate data. Use -r option to make it resumable.
org/embulk/exec/LocalExecutor.java:324:in `buildPartialExecuteException': org.embulk.exec.PartialExecutionException: org.jruby.exceptions.RaiseException: (NoMethodError) undefined method `fromRubyTime' for Java::OrgEmbulkSpiTime::Timestamp:Class
	from org/embulk/exec/LocalExecutor.java:462:in `doRun'
	from org/embulk/exec/LocalExecutor.java:40:in `access$000'
	from org/embulk/exec/LocalExecutor.java:353:in `run'
	from org/embulk/exec/LocalExecutor.java:350:in `run'
	from org/embulk/spi/Exec.java:21:in `doWith'
	from org/embulk/exec/LocalExecutor.java:350:in `run'
	from org/embulk/command/Runner.java:111:in `run'
	from org/embulk/command/Runner.java:64:in `main'
	from java/lang/reflect/Method.java:483:in `invoke'
	from file:/Users/mikami/work/embulk-work/embulk.jar!/embulk/command/embulk_run.rb:227:in `run'
	from classpath:embulk/command/embulk.rb:39:in `(root)'
	from classpath_3a_embulk/command/classpath:embulk/command/embulk.rb:39:in `(root)'
	from org/embulk/cli/Main.java:13:in `main'
Caused by:
(eval):26:in `initialize': org.jruby.exceptions.RaiseException: (NoMethodError) undefined method `fromRubyTime' for Java::OrgEmbulkSpiTime::Timestamp:Class
	from (eval):26:in `initialize'
	from file:/Users/mikami/work/embulk-work/embulk.jar!/embulk/schema.rb:81:in `write_record'
	from file:/Users/mikami/work/embulk-work/embulk.jar!/embulk/schema.rb:81:in `write_record'
	from file:/Users/mikami/work/embulk-work/embulk.jar!/embulk/page_builder.rb:10:in `add'
	from file:/Users/mikami/work/embulk-work/embulk.jar!/embulk/page_builder.rb:10:in `add'
	from /Users/mikami/.embulk/jruby/1.9/gems/embulk-plugin-mysql-0.0.1/lib/embulk/input_mysql.rb:73:in `run'
	from /Users/mikami/.embulk/jruby/1.9/gems/embulk-plugin-mysql-0.0.1/lib/embulk/input_mysql.rb:73:in `run'
	from /Users/mikami/.embulk/jruby/1.9/gems/embulk-plugin-mysql-0.0.1/lib/embulk/input_mysql.rb:40:in `connect'
	from /Users/mikami/.embulk/jruby/1.9/gems/embulk-plugin-mysql-0.0.1/lib/embulk/input_mysql.rb:40:in `connect'
	from /Users/mikami/.embulk/jruby/1.9/gems/embulk-plugin-mysql-0.0.1/lib/embulk/input_mysql.rb:60:in `run'
	from /Users/mikami/.embulk/jruby/1.9/gems/embulk-plugin-mysql-0.0.1/lib/embulk/input_mysql.rb:60:in `run'
	from file:/Users/mikami/work/embulk-work/embulk.jar!/embulk/input_plugin.rb:85:in `run'
	from file:/Users/mikami/work/embulk-work/embulk.jar!/embulk/input_plugin.rb:85:in `run'
	from Embulk$$InputPlugin$$JavaAdapter_236232597.gen:13:in `run'
	from Embulk$$InputPlugin$$JavaAdapter_236232597.gen:13:in `run'