fix(docs): update ubuntu / systemd service instructions

fixes #126

contrib/config

@@ -1,8 +1,7 @@
-music-path        
-cache-path        /tmp/gonic_cache
-db-path           /var/gonic/gonic.db
+music-path        <path to your music dir>
+podcast-path      <path to your podcasts dir>
+cache-path        <path to cache dir>
+db-path           /var/lib/gonic/gonic.db
 jukebox-enabled   false
 listen-addr       127.0.0.1:4747
-proxy-prefix      /gonic
 scan-interval     0
-podcast-path      

contrib/gonic.service

@@ -1,28 +1,17 @@
 [Unit]
-Description=Gonic service
-ConditionPathExists=/var/gonic/gonic
+Description=gonic service
+ConditionPathExists=/var/lib/gonic/
 After=network.target
 
 [Service]
 Type=simple
 User=gonic
 Group=gonic
-LimitNOFILE=1024
 
 Restart=on-failure
 RestartSec=10
 
-WorkingDirectory=/var/gonic/
-ExecStart=/var/gonic/gonic -config-path /var/gonic/config
-
-# make sure log directory exists and owned by syslog
-PermissionsStartOnly=true
-ExecStartPre=/bin/mkdir -p /var/log/gonic
-ExecStartPre=/bin/chown syslog:adm /var/log/gonic
-ExecStartPre=/bin/chmod 755 /var/log/gonic
-StandardOutput=syslog
-StandardError=syslog
-SyslogIdentifier=sleepservice
+ExecStart=/usr/local/bin/gonic -config-path /etc/gonic/config
 
 [Install]
 WantedBy=multi-user.target