Add gitlab-ci

.gitlab-ci.yml

+stages:
+  - test
+
+.tags: &tags
+  tags:
+    - librem5
+
+before_script:
+  - export DEBIAN_FRONTEND=noninteractive
+  - apt-get -y update
+  - apt-get -y install build-essential
+  - apt-get -y build-dep .
+
+test:
+  <<: *tags
+  image: debian:buster
+  stage: test
+  script:
+    - make test