Add code coverage via coveralls.io

Signed-off-by: Chris Aniszczyk <zx@twitter.com>

.travis.yml

@@ -2,3 +2,5 @@ language: java
 script: umask 0022 && mvn test
 jdk:
   - openjdk7
+after_success:
+  - mvn clean cobertura:cobertura coveralls:cobertura

README.md

@@ -1,4 +1,4 @@
-hRaven [![Build Status](https://travis-ci.org/twitter/hraven.png)](https://travis-ci.org/twitter/hraven)
+hRaven [![Build Status](https://travis-ci.org/twitter/hraven.png)](https://travis-ci.org/twitter/hraven) [![Coverage Status](https://coveralls.io/repos/twitter/hraven/branch.png?branch=master)](https://coveralls.io/r/twitter/hraven?branch=master)
 ==========
 
 hRaven collects run time data and statistics from map reduce jobs running on

pom.xml

@@ -179,6 +179,21 @@
           <attach>false</attach>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>cobertura-maven-plugin</artifactId>
+        <version>2.5.2</version>
+        <configuration>
+          <format>xml</format>
+          <maxmem>256m</maxmem>
+          <aggregate>true</aggregate>
+        </configuration>
+      </plugin>
+      <plugin>
+        <groupId>org.eluder.coveralls</groupId>
+        <artifactId>coveralls-maven-plugin</artifactId>
+        <version>2.2.0</version>
+      </plugin>
     </plugins>
   </build>
   <profiles>