Use adduser --system to prevent the script from failing

alumnihub_10.0_amd64/DEBIAN/postinst

@@ -1 +1,2 @@
-#!/bin/bash
+#!/bin/bash
+adduser --system alumnihub

alumnihub_10.0_amd64/DEBIAN/preinst

@@ -1,2 +1 @@
-#!/bin/bash
-useradd oqtane
+#!/bin/bash

alumnihub_10.0_amd64/etc/systemd/system/alumnihub.service

@@ -2,14 +2,14 @@
 Description=Alumnihub Webservice
 
 [Service]
-WorkingDirectory=/opt/oqtane
+WorkingDirectory=/opt/alumnihub
 ExecStart=/usr/bin/dotnet /opt/alumnihub/Oqtane.Server.dll
 Restart=always
 # Restart service after 10 seconds if the dotnet service crashes:
 RestartSec=5
 KillSignal=SIGINT
 SyslogIdentifier=alumnihub
-User=oqtane
+User=alumnihub
 Environment=ASPNETCORE_ENVIRONMENT=Production
 Environment=ASPNETCORE_URLS="http://127.0.0.1:5000"
 Environment=ASPNETCORE_FORWARDEDHEADERS_ENABLED=true