Add gitlab CI integration

Signed-off-by: Jelle van der Waa <jelle@archlinux.org>

.gitlab-ci.yml

+image: python:3.8-slim
+
+
+before_script:
+   - >
+     pip install pylint
+     pip install -r requirements.txt
+     pip install pylint
+     python manage.py collectstatic --noinput
+
+
+stages:
+  - lint
+  - test
+
+
+lint:
+  script:
+     - pylint devel main mirrors news packages releng templates todolists visualize *.py
+
+
+lint:
+  script:
+     - coverage run --rcfile .coveragerc manage.py test