sort out the network

.env-sample

@@ -1,3 +1,4 @@
+#!/usr/bin/bash
 # These env vars get templated into the configs in the respective containers via init scripts.
 #
 # If you want to make more customisations then either edit the templates to add more env variables below
@@ -8,21 +9,24 @@
 
 VOLUME_PATH=.
 DOMAIN=example.com
-HOMESERVER_FQDN=matrix.example.com
-ELEMENT_WEB_FQDN=element.example.com
-ELEMENT_CALL_FQDN=call.example.com
-MAS_FQDN=auth.example.com
+HOMESERVER_FQDN=matrix.$DOMAIN
+ELEMENT_WEB_FQDN=element.$DOMAIN
+ELEMENT_CALL_FQDN=call.$DOMAIN
+MAS_FQDN=auth.$DOMAIN
 
 REPORT_STATS=yes
 
 IDENTITY_SERVER_URL=https://vector.im
 
-MAIL_NOTIF_FROM_ADDRESS=noreply@example.com
-ABUSE_SUPPORT_EMAIL=abuse@example.com
-SECURITY_SUPPORT_EMAIL=security@example.com
+MAIL_NOTIF_FROM_ADDRESS=noreply@$DOMAIN
+ABUSE_SUPPORT_EMAIL=abuse@$DOMAIN
+SECURITY_SUPPORT_EMAIL=security@$DOMAIN
 
 MAS_CLIENT_ID="0000000000000000000SYNAPSE"
-MAS_EMAIL_FROM='"Authentication Service" <support@example.com>'
-MAS_EMAIL_REPLY_TO='"Authentication Service" <support@example.com>'
+MAS_EMAIL_FROM='"Matrix Authentication Service" <support@${DOMAIN}>'
+MAS_EMAIL_REPLY_TO='"Matrix Authentication Service" <support@${DOMAIN}>'
 
 COUNTRY=GB
+
+# as a convenience for creating /etc/hosts
+DOMAINS=($DOMAIN $HOMESERVER_FQDN $ELEMENT_WEB_FQDN $ELEMENT_CALL_FQDN $MAS_FQDN)