Update log_middleware.rb

Add option to get IP from `X-REAL-IP` header.

Author: Konstantin Krauss

lib/concise_logging/log_middleware.rb

@@ -6,7 +6,7 @@ def initialize(app)
 
     def call(env)
       request = ActionDispatch::Request.new(env)
-      Thread.current[:logged_ip] = request.ip
+      Thread.current[:logged_ip] = request.env['HTTP_X_REAL_IP'] || request.ip
       @app.call(env)
     ensure
       Thread.current[:logged_ip] = nil