add support for configuring server url. fixes #11

docker/Dockerfile

@@ -2,5 +2,12 @@ FROM nginx:alpine
 
 EXPOSE 80
 
+RUN apk add gettext
 COPY docker/nginx.conf /etc/nginx/conf.d/default.conf
+COPY docker/env.js.template /env.js.template
+COPY docker/docker-entrypoint.sh /docker-entrypoint.sh
+RUN chmod +x /docker-entrypoint.sh
 COPY dist/ /var/www/html/
+
+ENTRYPOINT ["/docker-entrypoint.sh"]
+CMD ["nginx", "-g", "daemon off;"]