Fix worker example (#1765)

* Fix worker example

* Clean worker example

* Improve docs

docs/docs/workers.md

@@ -116,18 +116,14 @@ A simple implementation example:
 
 ```python
 #!/usr/bin/env python
-import sys
-from rq import Connection, Worker
+from redis import Redis
+from rq import Worker
 
 # Preload libraries
 import library_that_you_want_preloaded
 
-# Provide queue names to listen to as arguments to this script,
-# similar to rq worker
-with Connection():
-    qs = sys.argv[1:] or ['default']
-
-    w = Worker(qs)
+# Provide the worker with the list of queues (str) to listen to.
+w = Worker(['default'], connection=Redis())
 w.work()
 ```