[opentracer] Final doc updates (#596)

README.md

@@ -3,6 +3,7 @@
 [![CircleCI](https://circleci.com/gh/DataDog/dd-trace-py/tree/master.svg?style=svg)](https://circleci.com/gh/DataDog/dd-trace-py/tree/master)
 [![Pyversions](https://img.shields.io/pypi/pyversions/ddtrace.svg?style=flat)](https://pypi.org/project/ddtrace/)
 [![PypiVersions](https://img.shields.io/pypi/v/ddtrace.svg)](https://pypi.org/project/ddtrace/)
+[![OpenTracing Badge](https://img.shields.io/badge/OpenTracing-enabled-blue.svg)](http://pypi.datadoghq.com/trace/docs/installation_quickstart.html#opentracing)
 
 `ddtrace` is Datadog's tracing library for Python.  It is used to trace requests
 as they flow across web servers, databases and microservices so that developers

docs/advanced_usage.rst

@@ -249,7 +249,8 @@ OpenTracing
 
 
 The Datadog opentracer can be configured via the ``config`` dictionary
-parameter which accepts the following described fields.
+parameter to the tracer which accepts the following described fields. See below
+for usage.
 
 +---------------------+---------------------------------------------------------+---------------+
 | Configuration Key   |  Description                                            | Default Value |
@@ -336,6 +337,15 @@ See also the `Python OpenTracing`_ repository for usage of the tracer.
 .. _Python OpenTracing: https://github.com/opentracing/opentracing-python
 
 
+**Alongside Datadog tracer**
+
+The Datadog OpenTracing tracer can be used alongside the Datadog tracer. This
+provides the advantage of providing tracing information collected by
+``ddtrace`` in addition to OpenTracing.  The simplest way to do this is to use
+the :ref:`ddtrace-run<ddtracerun>` command to invoke your OpenTraced
+application.
+
+
 **Opentracer API**
 
 .. autoclass:: ddtrace.opentracer.Tracer