Set MM_HOSTNAME to hostname -i.

core/assets/run.sh

@@ -25,10 +25,11 @@ function wait_for_postgres () {
 # Empty the config file.
 echo "# This file is autogenerated at container startup." > /etc/mailman.cfg
 
-# Check if $MM_HOSTNAME is set, if not, set it to a default value.
-# TODO: Factor this out to a function.
+# Check if $MM_HOSTNAME is set, if not, set it to the value returned by
+# `hostname -i` command to set it to whatever IP address is assigned to the
+# container.
 if [[ ! -v MM_HOSTNAME ]]; then
-	export MM_HOSTNAME='172.19.199.2'
+	export MM_HOSTNAME=`hostname -i`
 fi
 
 if [[ ! -v SMTP_HOST ]]; then