add gitlab ci

Dockerfile

@@ -0,0 +1,9 @@
+FROM python:3.9.0 as BUILD
+COPY requirements.txt .
+RUN pip install -r requirements.txt
+COPY mkdocs.yml .
+COPY docs docs
+RUN mkdocs build
+
+FROM nginx:latest
+COPY --from=BUILD /site/ /usr/share/nginx/html/