Require sudo.

Enable Docker service.

Enable Installs.

.travis.yml

@@ -3,14 +3,22 @@ language: java
 os:
   - linux
 
+sudo: required
+
+services:
+  - docker
+
 jdk:
   - oraclejdk8
 
-script: ./gradlew --info --refresh-dependencies clean build
-
 before_cache:
   - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
+
 cache:
   directories:
     - $HOME/.gradle/caches/
     - $HOME/.gradle/wrapper/
+
+install: true
+
+script: ./gradlew --info --refresh-dependencies clean build