Add Coveralls

.travis.yml

@@ -6,4 +6,4 @@ jdk:
   - openjdk8
 
 after_success:
-- mvn test jacoco:report coveralls:report -Pcoverage
+- mvn clean test jacoco:report coveralls:report

pom.xml

@@ -1,4 +1,5 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <parent>
     <groupId>org.jenkins-ci.plugins</groupId>
@@ -15,7 +16,8 @@
 
   <scm>
     <connection>scm:git:git://github.com/jenkinsci/${project.artifactId}-plugin.git</connection>
-    <developerConnection>scm:git:ssh://git@github.com/jenkinsci/${project.artifactId}-plugin.git</developerConnection>
+    <developerConnection>scm:git:ssh://git@github.com/jenkinsci/${project.artifactId}-plugin.git
+    </developerConnection>
     <url>https://github.com/jenkinsci/${project.artifactId}-plugin</url>
     <tag>HEAD</tag>
   </scm>
@@ -49,6 +51,9 @@
     <jenkins-declarative.version>1.1.2</jenkins-declarative.version>
     <jenkins-kubernetes-credentials.version>0.3.1</jenkins-kubernetes-credentials.version>
 
+    <!-- maven plugins versions -->
+    <maven-coveralls.version>4.3.0</maven-coveralls.version>
+    <maven-jacoco.version>0.8.1</maven-jacoco.version>
   </properties>
 
   <dependencies>
@@ -138,6 +143,30 @@
     </dependencies>
   </dependencyManagement>
 
+  <!-- for code coverage -->
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.eluder.coveralls</groupId>
+        <artifactId>coveralls-maven-plugin</artifactId>
+        <version>${maven-coveralls.version}</version>
+      </plugin>
+      <plugin>
+        <groupId>org.jacoco</groupId>
+        <artifactId>jacoco-maven-plugin</artifactId>
+        <version>${maven-jacoco.version}</version>
+        <executions>
+          <execution>
+            <id>prepare-agent</id>
+            <goals>
+              <goal>prepare-agent</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+
   <!-- get every artifact through repo.jenkins-ci.org, which proxies all the artifacts that we need -->
   <repositories>
     <repository>