Added Codecov integration

docs/src/main/asciidoc/README.adoc

@@ -1,6 +1,7 @@
 :jdkversion: 1.8
 
 image::https://circleci.com/gh/spring-cloud/spring-cloud-sleuth.svg?style=svg["CircleCI", link="https://circleci.com/gh/spring-cloud/spring-cloud-sleuth"]
+image::https://codecov.io/gh/spring-cloud/spring-cloud-sleuth/branch/master/graph/badge.svg["codecov", link="https://codecov.io/gh/spring-cloud/spring-cloud-sleuth"]
 image::https://badges.gitter.im/spring-cloud/spring-cloud-sleuth.svg[Gitter, link="https://gitter.im/spring-cloud/spring-cloud-sleuth?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge"]
 == Spring Cloud Sleuth
 

pom.xml

@@ -309,6 +309,48 @@
 				<module>benchmarks</module>
 			</modules>
 		</profile>
+		<profile>
+			<id>sonar</id>
+			<build>
+				<plugins>
+					<plugin>
+						<groupId>org.jacoco</groupId>
+						<artifactId>jacoco-maven-plugin</artifactId>
+						<executions>
+							<execution>
+								<id>pre-unit-test</id>
+								<goals>
+									<goal>prepare-agent</goal>
+								</goals>
+								<configuration>
+									<propertyName>surefireArgLine</propertyName>
+									<destFile>${project.build.directory}/jacoco.exec</destFile>
+								</configuration>
+							</execution>
+							<execution>
+								<id>post-unit-test</id>
+								<phase>test</phase>
+								<goals>
+									<goal>report</goal>
+								</goals>
+								<configuration>
+									<!-- Sets the path to the file which contains the execution data. -->
+									<dataFile>${project.build.directory}/jacoco.exec</dataFile>
+								</configuration>
+							</execution>
+						</executions>
+					</plugin>
+					<plugin>
+						<groupId>org.apache.maven.plugins</groupId>
+						<artifactId>maven-surefire-plugin</artifactId>
+						<configuration>
+							<!-- Sets the VM argument line used when unit tests are run. -->
+							<argLine>${surefireArgLine}</argLine>
+						</configuration>
+					</plugin>
+				</plugins>
+			</build>
+		</profile>
 	</profiles>
 
 </project>