Ruby-GetText Sample Rails Plugin.

Files
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* Rakefile: rake file for updatpo/makemo.

* init.rb:
     - initialize this plugin.

* lib/lang_helper.rb:
     - The main part of localized plugin.

* po/* (lang_helper.po[t])
     - Catalog files which translators edit. They are convert to
       mofiles by "rake makemo".
* locale/*
     - mo-files for this plugin.