adding README

Author: Ashish Aggarwal

integrations/opencensus/README.md

@@ -0,0 +1,52 @@
+# Opencensus Trace Exporter for Haystack
+
+The OpenCensus Haystack Trace Exporter is a trace exporter that exports data to haystack.
+
+To know about haystack checkout [here](https://expediadotcom.github.io/haystack/)
+
+## Quickstart
+
+#### Add the dependencies to your project
+For Maven add to your `pom.xml`:
+```xml
+<dependencies>
+  <dependency>
+    <groupId>io.opencensus</groupId>
+    <artifactId>opencensus-api</artifactId>
+    <version>0.17.0</version>
+  </dependency>
+  <dependency>
+    <groupId>io.opencensus</groupId>
+    <artifactId>opencensus-exporter-trace-haystack</artifactId>
+    <version>[0.2.1,)</version>
+  </dependency>
+  <dependency>
+    <groupId>io.opencensus</groupId>
+    <artifactId>opencensus-impl</artifactId>
+    <version>0.17.0</version>
+    <scope>runtime</scope>
+  </dependency>
+</dependencies>
+```
+
+For Gradle add to your dependencies:
+```groovy
+compile 'io.opencensus:opencensus-api:0.17.0'
+compile 'io.opencensus:opencensus-exporter-trace-haystack:0.2.1'
+runtime 'io.opencensus:opencensus-impl:0.17.0'
+```
+
+#### Register the exporter
+
+This will export traces to the haystack:
+
+```java
+public class MainClass {
+  public static void main(String[] args) throws Exception {
+    com.www.expedia.opencensus.exporter.trace.HaystackTraceExporter.createAndRegister(new GrpcAgentDispatcherConfig("haystack-agent", 35000), "my-service");
+    // ...
+  }
+}
+```
+
+You can look into the integration test [here](src/test/scala/com/www/expedia/opencensus/exporter/trace/HaystackExporterIntegrationSpec.scala)