Add GitLab CI script

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

Change-Id: Ic4b115858353774407fa4772c97473dd64fbdb57
diff --git a/.gitignore b/.gitignore
index 613b6da..149acc4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -21,6 +21,7 @@
 *\#
 !.github
 !.gitignore
+!.gitlab-ci.yml
 # /src/main/resources/
 /src/main/resources/server.properties
 /src/main/resources/krill.properties