Log Message:
Update ruby-logging to 1.8.0.

== 1.8.0 / 2012-09-13

Enhancements
- Appenders handle string encodings [issue #46]
- Support for diagnostic contexts [issues #23, #32, #42]
- Enable JSON formatting of log message [issue #34]

Bug Fixes
- Fix clash with ActiveSupport autoloader (chewie) [issue #39]