add circle ci config

.circleci/config.yml

@@ -0,0 +1,32 @@
+# Java Maven CircleCI 2.0 configuration file
+#
+# Check https://circleci.com/docs/2.0/language-java/ for more details
+#
+version: 2
+jobs:
+  build:
+    docker:
+      - image: circleci/openjdk:8-jdk
+
+    working_directory: ~/repo
+
+    environment:
+      MAVEN_OPTS: -Xmx3200m
+
+    steps:
+      - checkout
+      - restore_cache:
+          keys:
+          - v1-dependencies-{{ checksum "pom.xml" }}
+          # fallback to using the latest cache if no exact match is found
+          - v1-dependencies-
+
+      - run: mvn dependency:go-offline
+
+      - save_cache:
+          paths:
+            - ~/.m2
+          key: v1-dependencies-{{ checksum "pom.xml" }}
+
+      # run tests!
+      - run: ./mvnw clean verify