AMQP Consumer plugin (#1678)

plugins/outputs/amqp/README.md

@@ -1,13 +1,18 @@
 # AMQP Output Plugin
 
-This plugin writes to a AMQP exchange using tag, defined in configuration file
-as RoutingTag, as a routing key.
+This plugin writes to a AMQP 0-9-1 Exchange, a promenent implementation of this protocol being [RabbitMQ](https://www.rabbitmq.com/).
+
+Metrics are written to a topic exchange using tag, defined in configuration file as RoutingTag, as a routing key.
 
 If RoutingTag is empty, then empty routing key will be used.
 Metrics are grouped in batches by RoutingTag.
 
 This plugin doesn't bind exchange to a queue, so it should be done by consumer.
 
+For an introduction to AMQP see:
+- https://www.rabbitmq.com/tutorials/amqp-concepts.html
+- https://www.rabbitmq.com/getstarted.html
+
 ### Configuration:
 
 ```
@@ -18,6 +23,8 @@ This plugin doesn't bind exchange to a queue, so it should be done by consumer.
   ## AMQP exchange
   exchange = "telegraf"
   ## Auth method. PLAIN and EXTERNAL are supported
+  ## Using EXTERNAL requires enabling the rabbitmq_auth_mechanism_ssl plugin as
+  ## described here: https://www.rabbitmq.com/plugins.html
   # auth_method = "PLAIN"
   ## Telegraf tag to use as a routing key
   ##  ie, if this tag exists, it's value will be used as the routing key