README.md in ougai-1.8.0-java vs README.md in ougai-1.8.1

- old
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@@ -1,9 +1,9 @@
 Ougai
 =====
 
 [![Gem Version](https://badge.fury.io/rb/ougai.svg)](https://badge.fury.io/rb/ougai)
-[![document](https://img.shields.io/badge/document-1.7.0-green.svg)](http://www.rubydoc.info/gems/ougai/)
+[![document](https://img.shields.io/badge/document-1.8.1-green.svg)](http://www.rubydoc.info/gems/ougai/)
 [![Build Status](https://travis-ci.org/tilfin/ougai.svg?branch=master)](https://travis-ci.org/tilfin/ougai)
 [![Code Climate](https://codeclimate.com/github/tilfin/ougai/badges/gpa.svg)](https://codeclimate.com/github/tilfin/ougai)
 [![Test Coverage](https://codeclimate.com/github/tilfin/ougai/badges/coverage.svg)](https://codeclimate.com/github/tilfin/ougai/coverage)
 
 A structured logging system is capable of handling a message, structured data or an exception easily.