Importing into a fresh repository.

+FROM docker.brainfood.com/dumb-init
+
+ADD /overlay/ /
+
+# export DEBIAN_FRONTEND=noninteractive RUNLEVEL=1
+RUN ["apt-docker", \
+	"-y", "install", "bsd-mailx", "postfix", "dovecot-imapd", \
+	";" ]
+
+EXPOSE 25 143
+VOLUME ["/home"]

+version: '2'
+
+services:
+        build:
+                image: docker.brainfood.com/mail
+                build:
+                        context: .
+                        args:
+                                - http_proxy
+                                - https_proxy
+

+#!/bin/bash
+
+HOSTNAME=$(hostname -f)
+
+postconf -e \
+	"myhostname = $HOSTNAME" \
+	"mydestination = $HOSTNAME, localhost.localdomain, localhost" \
+	"mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 10.0.0.0/8 172.0.0.0/8"\
+	"inet_protocols = all" \
+	"relayhost = $POSTFIX_RELAYHOST" \
+	"virtual_maps = hash:/etc/postfix/virtual, regexp:/etc/postfix/virtual-regexp" \
+	"home_mailbox = Maildir/" \
+	&& true
+
+touch /etc/postfix/virtual
+postmap /etc/postfix/virtual
+
+if [[ $POSTFIX_REDIRECT_MAIL_LOCALHOST ]]; then
+	echo "/.+@.+/ $POSTFIX_REDIRECT_MAIL_LOCALHOST@localhost" > /etc/postfix/virtual-regexp
+	if ! getent passwd $POSTFIX_REDIRECT_MAIL_LOCALHOST > /dev/null; then
+		adduser --disabled-password --gecos "$POSTFIX_REDIRECT_MAIL_LOCALHOST" $POSTFIX_REDIRECT_MAIL_LOCALHOST
+	fi
+	echo "$POSTFIX_REDIRECT_MAIL_LOCALHOST:$POSTFIX_REDIRECT_MAIL_LOCALHOST" | chpasswd
+else
+	: > /etc/postfix/virtual-regexp
+fi
+

+mail_location = maildir:~/Maildir
+disable_plaintext_auth = no