Update Azure Monitor exporter for Python (census-instrumentation#696)

* update Azure Monitor exporter for Python

* update ToC

* add notice about 100% sample rate

content/exporters/supported-exporters/Python/AzureMonitor.md

@@ -0,0 +1,58 @@
+---
+title: "Azure Monitor"
+date: 2019-06-10
+draft: false
+weight: 3
+class: "resized-logo"
+aliases: [/guides/exporters/supported-exporters/python/azure-monitor]
+logo: /img/partners/microsoft_logo.svg
+---
+
+- [Introduction](#introduction)
+- [Installing the exporter](#installing-the-exporter)
+- [Creating the exporter](#creating-the-exporter)
+- [Viewing your traces](#viewing-your-traces)
+
+## Introduction
+[Azure Monitor](https://docs.microsoft.com/en-us/azure/azure-monitor/) is an
+extensible Application Performance Management (APM) service for web developers
+on multiple platforms. Offered by Microsoft Azure, it's a complete at-scale
+telemetry and monitoring solution.
+
+## Installing the exporter
+The Azure Monitor exporter can be installed from pip by
+```shell
+pip install opencensus-ext-azure
+```
+
+## Creating the exporter
+To create the exporters, you'll need to:
+
+* Use an active Azure account, [sign up for free](https://azure.microsoft.com/en-us/free/) if you haven't already.
+* Create an Azure Monitor resource and get the instrumentation key, more information can be found
+  [here](https://docs.microsoft.com/en-us/azure/azure-monitor/app/create-new-resource).
+* Put the instrumentation key in `APPINSIGHTS_INSTRUMENTATIONKEY` environment variable.
+* Create the exporters in code.
+
+{{% notice tip %}}
+For demo purpose, the example code is using 100% sample rate.
+You should specify a reasonable sample rate for production environment.
+{{% /notice %}}
+
+{{<highlight python>}}
+from opencensus.ext.azure.trace_exporter import AzureExporter
+from opencensus.trace.samplers import ProbabilitySampler
+from opencensus.trace.tracer import Tracer
+
+tracer = Tracer(exporter=AzureExporter(), sampler=ProbabilitySampler(1.0))
+
+with tracer.span(name='hello'):
+    print('Hello, World!')
+{{</highlight>}}
+
+For more information, please refer to [README](https://github.com/census-instrumentation/opencensus-python/tree/master/contrib/opencensus-ext-azure).
+
+## Viewing your traces
+You can view the traces by using [Search](https://docs.microsoft.com/en-us/azure/azure-monitor/app/diagnostic-search),
+[Transaction Diagnostics](https://docs.microsoft.com/en-us/azure/azure-monitor/app/transaction-diagnostics)
+or [Application Map](https://docs.microsoft.com/en-us/azure/azure-monitor/app/app-map).