Update Dockerfile

Dockerfile

@@ -6,6 +6,10 @@ EXPOSE 25
 
 VOLUME ["/var/log", "/var/spool/postfix"]
 
+RUN useradd postfix --gid 0 --uid 1001
+
+USER postfix
+
 RUN rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 && \
     yum updateinfo -y && \
     yum update -y glibc && \
@@ -14,6 +18,8 @@ RUN rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 && \
     yum install -y python34-devel postfix cyrus-sasl cyrus-sasl-plain mailx && \
     yum clean all
 
+RUN useradd -G cartoons jerry
+
 RUN chmod -Rf g+w /etc/postfix && \
     chmod -Rf g+w /var/log && \
     chmod -Rf g+w /var/spool/postfix && \