Add Unbound as better DNSSEC enabled resolver

data/Dockerfiles/unbound/Dockerfile

@@ -0,0 +1,21 @@
+FROM alpine:3.6
+
+LABEL maintainer "Andre Peters <andre.peters@servercow.de>"
+
+RUN apk add --update --no-cache \
+	curl \
+	unbound \
+	bash \
+	openssl \
+	drill \
+	&& curl -o /etc/unbound/root.hints https://www.internic.net/domain/named.cache \
+	&& chown root:unbound /etc/unbound \
+	&& chmod 775 /etc/unbound
+
+COPY unbound.conf /etc/unbound/unbound.conf
+
+EXPOSE 53/udp 53/tcp
+
+COPY docker-entrypoint.sh /docker-entrypoint.sh
+
+ENTRYPOINT ["/docker-entrypoint.sh"]