pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.gwtproject.tutorial</groupId>
  <artifactId>gwt-polymer-todo-list</artifactId>
  <packaging>pom</packaging>
  <version>1.9.3.1</version>

  <modules>
    <module>widgets-todo-list</module>
    <module>elements-todo-list</module>
  </modules>

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <executions>
          <execution>
            <phase>process-resources</phase>
            <configuration>
              <tasks>
                <delete dir="www" />
                <mkdir dir="www" />
                <copy todir="www">
                  <fileset dir="widgets-todo-list/target/gwt-polymer-widgets-todo-${project.version}" includes="**/*" />
                  <fileset dir="elements-todo-list/target/gwt-polymer-elements-todo-${project.version}" includes="**/*" />
                </copy>
                <delete dir="www/WEB-INF" />
                <delete dir="www/META-INF" />
              </tasks>
            </configuration>
            <goals>
              <goal>run</goal>
            </goals>
          </execution>
        </executions>
      </plugin>  
    </plugins>
  </build>
</project>