public/git/Add-PSTSGitRepositoryInit.ps1

function Add-PSTSGitRepositoryInit
{
    param(
         [Parameter(Mandatory=$true)][string] $project,
         [Parameter(Mandatory=$true)][string] $repoName

    )

    $id = $(Get-PSTSGitRepository -project $project | Where-Object {$_.name -eq $repoName} | Select-Object -ExpandProperty id )
    if ([String]::IsNullOrEmpty($id))
    {
        Write-Error "$repoName doesn't exist in $project !!"
        return 128
    }
    else
    {
        Write-Debug "$repoName exists in $project"
        $newObjectId = Get-PSTSGitRepositoryRef -project devops -id "$id" | Where-Object {$_.name -eq "refs/heads/master" }| Select-Object -ExpandProperty objectId
        $payload= New-Object -TypeName "PSObject"
        $payload | Add-Member -MemberType NoteProperty "name" -Value "refs/heads/$refName"
        $payload | Add-Member -MemberType NoteProperty "newObjectId" -Value   "$newObjectId"
        $payload | Add-Member -MemberType NoteProperty "oldObjectId" -Value   "0000000000000000000000000000000000000000"


        $body = '{
            "refUpdates": [
              {
                "name": "refs/heads/master",
                "oldObjectId": "0000000000000000000000000000000000000000"
              }
            ],
            "commits": [
              {
                "comment": "Initial commit.",
                "changes": [
                  {
                    "changeType": "add",
                    "item": {
                      "path": "/readme.md"
                    },
                    "newContent": {
                      "content": "My first file!",
                      "contentType": "rawtext"
                    }
                  }
                ]
              }
            ]
          }'

        $content = `
        _PSTSAPI `
            -resource "git/repositories/$id/pushes" `
            -method "POST" `
            -project $project `
            -repositoryId $id `
            -body $("$body" )  `
            -contentType "application/json" `
            -apiVersion "api-version=5.1-preview"

        return [Object]$content
   }

}