Also build docs in Docker container (#255)

Co-authored-by: Duco <git@ducode.org>

Dockerfile

@@ -12,11 +12,18 @@ WORKDIR /app
 COPY . ./
 RUN cd gui && npm install && npm run build
 
+# Build docs
+FROM python:slim-bullseye AS doc-build-env
+WORKDIR /app
+COPY . ./
+RUN cd docs/httpl-docs && pip install mkdocs && python sync.py && mkdocs build && cp -r site /app
+
 # Build runtime image
 FROM mcr.microsoft.com/dotnet/aspnet:6.0
 WORKDIR /app
 COPY --from=build-env /app/out .
 COPY --from=gui-build-env /app/gui/dist ./gui
+COPY --from=doc-build-env /app/site/. ./gui/docs
 ENV inputFile=/var/httplaceholder
 RUN mkdir /var/httplaceholder
 ENTRYPOINT ["dotnet", "HttPlaceholder.dll"]