Add usage instructions (#300)

Author: tstirrat15

packages/opencensus-exporter-jaeger/README.md

@@ -5,9 +5,48 @@ OpenCensus Jaeger Exporter allows the user to send collected traces with OpenCen
 
 This project is still at an early stage of development. It's subject to change.
 
+## Installation
+
+Install OpenCensus Jaeger Exporter with:
+```bash
+npm install @opencensus/nodejs
+npm install @opencensus/exporter-jaeger
+```
+
+## Usage
+
+Instance the exporter on your application and pass the options, it must contain a service name and, optionaly, an URL. If no URL is passed, `http://localhost:9411/api/v2/spans` is used as default.
+
+For ES6:
+
+```javascript
+import tracing from '@opencensus/nodejs';
+import { JaegerTraceExporter } from '@opencensus/exporter-jaeger';
+
+const options = {
+  serviceName: 'my-service';
+  tags: []; // optional
+  host: localhost; // optional
+  port: 6832; // optional
+  maxPacketSize: 65000; // optional
+}
+var exporter = new JaegerTraceExporter(options);
+```
+
+Now, register the exporter and start tracing.
+
+```javascript
+tracing.start({'exporter': exporter});
+```
+
+or
+
+```javascript
+tracing.registerExporter(exporter).start();
+```
 
 ## Useful links
-- To know more about Jaeger, visit: <https://cloud.google.com/docs/authentication/getting-started>
+- To know more about Jaeger, visit: <https://www.jaegertracing.io/docs/1.8/getting-started/>
 - For more information on OpenCensus, visit: <https://opencensus.io/>
 - To checkout the OpenCensus for Node.js, visit: <https://github.com/census-instrumentation/opencensus-node>
 - For help or feedback on this project, join us on [gitter](https://gitter.im/census-instrumentation/Lobby)