read /etc/environment for CAL_USR/CAL_PWD

cal.service

@@ -7,6 +7,7 @@ After=network-online.target
 User=nobody
 Type=simple
 WorkingDirectory=/usr/local/share/cal
+EnvironmentFile=/etc/environment
 ExecStart=/bin/bash -l -c 'source bin/activate;./server'
 Restart=always