Powershell script to add multiple users to the Administators and Remote Desktop Users group to multiple the remote servers

addusers.ps1

$servers = "server1","server2"
$users = "user1","user2","user3"
$domain= "domain"
$admin = "admin"
$admin_user = Get-Credential -Credential "$domain\$admin"

ForEach ($server in $servers) {
    Write-Host $server;
    $admin_grp = [ADSI]::new("WinNT://$server/Administrators,group",$admin_user.UserName,$admin_user.GetNetworkCredential().Password);
    $rdp_grp = [ADSI]::new("WinNT://$server/Remote Desktop Users,group",$admin_user.UserName,$admin_user.GetNetworkCredential().Password);

  foreach( $user in $users) {
        Write-Host $user;
        $aduser = ([ADSI]"WinNT://$domain/$user,user").Path;
        $admin_grp.Add($aduser);
        $rdp_grp.Add($aduser);
    }
}