Use nginx to serve static files

This should keep easy requests out the app event loop, hopefully improving response time

Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update --yes --quiet && apt-get install --yes --quiet --no-install-r
     libpq-dev \
     curl \
     git \
+    nginx \
     # wand dependencies
     libmagickwand-6.q16-6 libmagickwand-6.q16hdri-6 \
     && apt-get autoremove && rm -rf /var/lib/apt/lists/*
@@ -33,6 +34,8 @@ ENV PATH=$VIRTUAL_ENV/bin:$PATH \
 
 EXPOSE 8000
 
+RUN ln -fs /app/etc/nginx.conf /etc/nginx/sites-available/default
+
 USER website
 
 RUN python -m venv $VIRTUAL_ENV