Add CI config

.gitlab-ci.yml

+# Use Ubuntu Linux docker image
+image: ubuntu:rolling
+
+
+# Defines stages which are to be executed
+stages:
+  - build
+
+# Setup for scripts
+before_script:
+- export DEBIAN_FRONTEND=noninteractive
+- apt update
+- apt install pandoc texlive-fonts-recommended texlive-xetex -y
+  
+
+# Configure and build the project
+build_pdf:
+  stage: build
+  script:
+    - ./build.sh
+  artifacts:
+    paths:
+      - pdf
+    expire_in: 4 weeks