Add sample configuration and documentation (#1)

Reviewed-on: #1

deploy_configs/mail4one.service

@@ -1,4 +1,7 @@
-# mail4one.service
+# This file should be copied to /etc/systemd/system/mail4one.service 
+# Quickstart
+# systemctl daemon-reload
+# systemctl enable --now mail4one.service 
 
 [Unit]
 Description=Personal Mail server
@@ -7,12 +10,14 @@ After=network.target network-online.target
 Requires=network-online.target
 
 [Service]
+
+# This user should already exist. See mail4one.conf for creating user with sysusers
 User=mail4one
 ExecStart=/usr/local/bin/mail4one --config /etc/mail4one/config.json
 
+# Below allows to bind to port < 1024. Standard ports are 25, 465, 995
 AmbientCapabilities=CAP_NET_BIND_SERVICE
 CapabilityBoundingSet=CAP_NET_BIND_SERVICE
-NoNewPrivileges=yes
 
 StateDirectory=mail4one/certs mail4one/mails
 StateDirectoryMode=0750
@@ -23,6 +28,7 @@ ProtectSystem=strict
 PrivateTmp=true
 ProtectHome=yes
 ProtectProc=invisible
+NoNewPrivileges=yes
 
 [Install]
 WantedBy=multi-user.target