add descriptino for queuing section

README.md

@@ -585,6 +585,8 @@ Web-based project management and bug tracking systems.
 
 **[`^        back to top        ^`](#awesome-sysadmin)**
 
+[Message queues](https://en.wikipedia.org/wiki/Message_queue) and [message broker](https://en.wikipedia.org/wiki/Message_broker) software, typically used for inter-process communication (IPC), or for inter-thread communication within the same process.
+
 - [ActiveMQ](https://activemq.apache.org/) - Java message broker. ([Source Code](https://github.com/apache/activemq)) `Apache-2.0` `Java`
 - [BeanstalkD](https://beanstalkd.github.io/) - A simple, fast work queue. ([Source Code](https://github.com/beanstalkd/beanstalkd)) `MIT` `C`
 - [Gearman](http://gearman.org/) - Fast multi-language queuing/job processing platform. ([Source Code](https://github.com/gearman/gearmand)) `BSD-3-Clause` `C++`