Added an option to specify demo user, will be created on startup if it does not exist

internal/routes/userlogin.go

@@ -34,7 +34,7 @@ func PostLoginHandler(ac appcontext.AppContext) {
 		}
 		username = user.Username
 	} else {
-		username = "demo"
+		username = ac.Config.DemoUsername
 	}
 
 	var jwtToken string