Run tests with docker

Added documentation on how to use docker to run the testsuite

Author: christiaan

README.md

@@ -111,8 +111,15 @@ open.then(function(conn) {
 
     npm test
 
-Best run with a locally-installed RabbitMQ, but you can point it at
-another using the environment variable `URL`; e.g.,
+To run the tests RabbitMQ is required. Either install it with your package
+manager or use [docker][] to run a RabbitMQ instance.
+
+    docker run -d --name amqp.test -p 5672:5672 rabbitmq
+
+If prefer not to run RabbitMQ locally it is also possible to use a instance
+of RabbitMQ hosted elsewhere. Use the `URL` environment variable to configure a
+different amqp host to connect to. One such host is dev.rabbitmq.com which you
+can also use to run the tests like so.
 
     URL=amqp://dev.rabbitmq.com npm test
 
@@ -146,3 +153,4 @@ really only useful for checking the kind and formatting of the errors.
 [tutes]: https://github.com/squaremo/amqp.node/tree/master/examples/tutorials
 [rabbitmq-tutes]: http://www.rabbitmq.com/getstarted.html
 [changelog]: https://github.com/squaremo/amqp.node/blob/master/CHANGELOG.md
+[docker]: https://www.docker.com/