emu-assign-groups.ps1

# Conntect to Azure AD
Connect-AzureAD
# Get the Enterprise Application for GitHub Enterprise with EMU
$githubEMUenterpriseApp = Get-AzureADServicePrincipal -Filter "Displayname eq 'GitHub Enterprise Managed User'"
# Get all groups you want to assign, based on their name
$groups = Get-AzureADGroup -all $true | Where-Object {$_.DisplayName -like "Dev*"} | Select displayname,objectid
# Loop through all groups and assign them to your Enterprise Application Role
# Approles[1] Billing Manager 
# Approles[2] User
# Approles[3] Enterprise Owner
ForEach ($group in $groups) {
  Try {
      New-AzureADGroupAppRoleAssignment -ObjectId $group.ObjectId -PrincipalId $group.ObjectId -Id $githubEMUenterpriseApp.Approles[2].id -ResourceId $githubEMUenterpriseApp.ObjectId -ErrorAction Stop
      [PSCustomObject]@{
          GroupName = $group.displayname
          AppliciationAssigned = $true
      }
    }
    catch {
      [PSCustomObject]@{
          GroupName = $group.displayname
          AppliciationAssigned = $false
      }
    }
}

# Credit goes to LazyAdmin Ruud for his helpful blog post on https://lazyadmin.nl/powershell/add-users-to-azure-ad-application-with-powershell/