dovecot, postfix: fix uid and gid

Author: namachan10777

dovecot/Dockerfile

@@ -4,7 +4,12 @@ ARG POSTFIX_GID=4005
 ARG DOVECOT_UID=4006
 ARG DOVECOT_GID=4006
 RUN apt-get update && apt-get install -qy dovecot-core dovecot-imapd
-RUN useradd -u $POSTFIX_UID -g $POSTFIX_GID -s /bin/false postfix
-RUN useradd -u $DOVECOT_UID -g $DOVECOT_GID -s /bin/false dovecot
+
+RUN groupadd postfix -g $POSTFIX_GID && \
+    useradd postfix -u ${POSTFIX_UID} -g postfix -s /bin/false && \
+    gpasswd -a mail postfix
+
+RUN groupmod dovecot -g ${DOVECOT_GID} && \
+    usermod dovecot -u $DOVECOT_UID -g $DOVECOT_GID -s /bin/false
 
 CMD [ "/usr/sbin/dovecot", "-F" ]

postfix/Dockerfile

@@ -4,8 +4,11 @@ ARG POSTFIX_UID=4005
 ARG POSTFIX_GID=4005
 ARG DOVECOT_UID=4006
 ARG DOVECOT_GID=4006
-RUN apt-get update && apt-get install -qy postfix dovecot-core dovecot-imapd
-RUN useradd -u $POSTFIX_UID -g $POSTFIX_GID -s /bin/false postfix
-RUN useradd -u $DOVECOT_UID -g $DOVECOT_GID -s /bin/false dovecot
+RUN apt-get update && apt-get install -qy postfix
+
+RUN groupadd -g ${DOVECOT_GID} dovecot && \
+    useradd -u $DOVECOT_UID -g dovecot -s /bin/false dovecot
+RUN groupmod -g ${POSTFIX_GID} postfix && \
+    usermod -u ${POSTFIX_UID} -g ${POSTFIX_GID} postfix
 
 CMD [ "/usr/sbin/postfix" "start-fg" ]