Add .gitlab-ci.yml

.gitlab-ci.yml

+# This file is a template, and might need editing before it works on your project.
+# use the official gcc image, based on debian
+# can use verions as well, like gcc:5.2
+# see https://hub.docker.com/_/gcc/
+image: gcc
+
+build:
+  stage: build
+  script: 
+    - make
+  artifacts:
+    paths:
+      - ./
+