add travis yaml for CI build

.travis.yml

@@ -0,0 +1,24 @@
+sudo: required
+dist: trusty
+language: java
+
+jdk:
+  - oraclejdk8
+
+before_install:
+  - gradle wrapper
+
+install: true
+
+script:
+  - ./gradlew clean build
+
+before_cache:
+  - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
+  - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
+
+cache:
+  directories:
+    - "$HOME/.m2/repository"
+    - "$HOME/.gradle/caches/"
+    - "$HOME/.gradle/wrapper/"