Add GitLab CI script

Fresh builds then can be used from other CI/CD scripts.

Change-Id: Ic4b115858353774407fa4772c97473dd64fbdb57
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
new file mode 100644
index 0000000..45dff3a
--- /dev/null
+++ b/.gitlab-ci.yml
@@ -0,0 +1,20 @@
+image: maven:3-eclipse-temurin-17-alpine
+
+stages:
+    - build
+
+cache:
+  paths:
+    - .m2/repository
+
+variables:
+  MAVEN_OPTS: "-Dmaven.repo.local=$CI_PROJECT_DIR/.m2/repository"
+
+
+build:
+  stage: build
+  artifacts:
+    paths:
+      - target/Krill-Indexer.jar
+  script:
+    - mvn clean package