Add config file for public travis CI

Added a script for Travis to build xenon in background and
log output in a file. This is workaround for limitation of
Travis which does not allow log output to be more than
4MB for better UI and API experience. But xenon tests output
more than 4MB of logs. After the build is completed, this script
outputs last 1000 lines for debugging purpose.

Also updated git-commit-id-plugin with latest version because
old version was not working good on travis CI and was throwing errors

Change-Id: I466a5a23fcbe5107f06e0999473757b5e9b3350a

.travis.yml

@@ -0,0 +1,14 @@
+language: java
+sudo: required
+install: true
+dist: trusty
+
+jdk:
+  - oraclejdk8
+
+script:
+  - ./bg-build.sh
+
+cache:
+  directories:
+    - '$HOME/.m2/repository'

README.md

@@ -1,4 +1,4 @@
-# 1.0 Brief Introduction to Xenon
+# 1.0 Brief Introduction to Xenon [![Build Status](https://travis-ci.org/vmware/xenon.svg?branch=master)](https://travis-ci.org/vmware/xenon)
 
 ## 1.1 Xenon Highlights
 Xenon is a framework for writing small REST-based services. (Some people call them microservices.)

bg-build.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+# Script to build xenon in background for Travis CI.
+# Travis CI does not allow output log to be more than 4MB. To overcome this
+# limitation we run the mvn build command in background in this script
+# and redirect the output in a log file. At the end of build we print last
+# few lines from the log file on to the console for debugging purpose.
+
+set -ex
+
+export WORKING_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+export OUTPUT_FILE=$WORKING_DIR/output.out
+touch $OUTPUT_FILE
+
+print_output() {
+   echo "Last 1000 lines of output:"
+   tail -1000 $OUTPUT_FILE
+}
+
+handle_error() {
+  echo "ERROR: Caught an error in the build."
+  print_output
+  exit 1
+}
+
+trap 'handle_error' ERR
+
+bash -c "while true; do echo \$(date) - building xenon...; sleep 30s; done" &
+LOOP_PID=$!
+
+./mvnw install -P coverage >> $OUTPUT_FILE 2>&1
+
+print_output
+kill -9 $LOOP_PID

xenon-common/pom.xml

@@ -86,7 +86,7 @@
       <plugin>
         <groupId>pl.project13.maven</groupId>
         <artifactId>git-commit-id-plugin</artifactId>
-        <version>2.1.10</version>
+        <version>2.2.2</version>
         <executions>
           <execution>
             <goals>
@@ -99,6 +99,9 @@
           <generateGitPropertiesFile>true</generateGitPropertiesFile>
           <generateGitPropertiesFilename>src/main/resources/xenon.git.properties</generateGitPropertiesFilename>
           <excludeProperties>
+            <excludeProperty>git.tags*</excludeProperty>
+            <excludeProperty>git.dirty*</excludeProperty>
+            <excludeProperty>git.closest.*</excludeProperty>
             <excludeProperty>git.branch.*</excludeProperty>
             <excludeProperty>git.build.*</excludeProperty>
             <excludeProperty>git.commit.message.*</excludeProperty>