add GitLab Runner configuration file (see http://docs.gitlab.com/ce/ci/yaml/README.html )

.gitlab-ci.yml

+image: gcc
+stages:
+  - build
+  - test
+
+build_job:
+  stage: build
+  script:
+    - make
+
+test_job:
+  stage: test
+  script:
+    - ./main.o