Merge branch 'ci' into 'master'

Added CI Pipline

See merge request cda/rcda!1

.gitlab-ci.yml

@@ -0,0 +1,21 @@
+build:
+  stage: build
+  image: nixos/nix
+  variables:
+    QT_QPA_PLATFORM: "offscreen"
+  before_script:
+    - export XDG_RUNTIME_DIR="$(mktemp -p $(pwd) -d)/"
+    - mkdir output
+  script:
+    - nix run nixpkgs.tiled -c tiled --export-map json w17.tmx output/w17.json
+  after_script:
+    - cp -R imgs output/imgs
+  artifacts:
+    untracked: false
+    paths:
+      - output
+    expire_in: 1 week
+    when: always
+  tags:
+    - as6766
+