Move into stretch subdirectory

stretch/Dockerfile

@@ -0,0 +1,18 @@
+FROM debian:stretch-slim
+MAINTAINER Bytemark Hosting "support@bytemark.co.uk"
+
+# Install exim4
+ENV DEBIAN_FRONTEND noninteractive
+RUN set -ex; \
+    apt-get update; \
+    apt-get install -y exim4-daemon-light; \
+    apt-get clean
+
+# Copy the main script.
+COPY docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
+
+# We expose exim on port 25.
+EXPOSE 25/tcp
+
+ENTRYPOINT [ "docker-entrypoint.sh" ]
+CMD [ "exim", "-bdf", "-v", "-q30m" ]