Add dockerfile and enable Docs build

docs/Dockerfile

@@ -0,0 +1,22 @@
+FROM python:3-alpine
+
+COPY requirements.txt /requirements.txt
+
+ARG version=master
+ENV VERSION=$version
+
+RUN pip install -r /requirements.txt \
+ && apk add --no-cache nginx curl \
+ && mkdir /run/nginx
+
+COPY ./nginx.conf /etc/nginx/conf.d/default.conf
+COPY . /docs
+
+RUN mkdir -p /build/$VERSION \
+ && sphinx-build /docs /build/$VERSION
+
+EXPOSE 80/tcp
+
+CMD nginx -g "daemon off;"
+
+HEALTHCHECK CMD curl -f -L http://localhost/ || exit 1