Documment config.log_formatter added on 51aeae9

[ci skip]

Author: rafaelfranca

guides/source/configuring.md

@@ -103,6 +103,8 @@ numbers. New applications filter out passwords by adding the following `config.f
 
 * `config.force_ssl` forces all requests to be under HTTPS protocol by using `ActionDispatch::SSL` middleware.
 
+* `config.log_formatter` defines the formatter of the Rails logger. This option defaults to a instance of `ActiveSupport::Logger::SimpleFormatter` for all modes except production, where it defaults to `Logger::Formatter`.
+
 * `config.log_level` defines the verbosity of the Rails logger. This option defaults to `:debug` for all modes except production, where it defaults to `:info`.
 
 * `config.log_tags` accepts a list of methods that respond to `request` object. This makes it easy to tag log lines with debug information like subdomain and request id — both very helpful in debugging multi-user production applications.