Add user programmtically with role in wordpress

<?php
require ("wp-load.php");

if ( $_REQUEST['names'] != "" && $_REQUEST['emails'] != "" && $_REQUEST['password'] != "" && $_REQUEST['role'] != "" && $_REQUEST['tech'] != "" ) {
 global $wpdb;
 if ( !username_exists( $_REQUEST['emails'] ) ) {

  $device_id   = $_REQUEST['device_id'];
 
  $name    = $_REQUEST['names'];
  $user_login  = $_REQUEST['emails'];
  $user_email  = $_REQUEST['emails'];
  $user_pass   = $_REQUEST['password'];
  $role        = $_REQUEST['role'];
  $tech        = $_REQUEST['tech'];
/*   $name    = 'kathir';
  $user_login  = 'kathiresa';
  $user_email  = 'katir@gmail.com';
  $user_pass   = 'kathir';
  $role = 'php';
  $tech = 'drupal';*/
 
  $userdata   = compact('name', 'user_login', 'user_email', 'user_pass');
  $user_id   = wp_insert_user( $userdata );

  $user = new WP_User( $user_id );
  //add role
  $user->set_role( $role );

  //add group for user
  $groups = $wpdb->get_results( " SELECT ID  FROM it_uam_accessgroups WHERE groupname = '".$tech."' ");
  $gid = $groups[0]->ID;
  $wpdb->insert( 'it_uam_accessgroup_to_object', array( 'object_id' => $user_id, 'object_type' => 'user', 'group_id' => $gid ), array( '%d', '%s', '%d' ) );


  if ( $_FILES['image_url']['name'] != "" ) {
   global $wpdb;
   //For Uploading photo from front End
   if (!function_exists('wp_generate_attachment_metadata')){
       require_once(ABSPATH . "wp-admin" . '/includes/image.php');
       require_once(ABSPATH . "wp-admin" . '/includes/file.php');
       require_once(ABSPATH . "wp-admin" . '/includes/media.php');
      }
   $overrides = array( 'test_form' => false);
   $file = wp_handle_upload($_FILES['image_url'], $overrides);
   $file['url'];
 
   $content = $file['url'];
  }
 
  update_user_meta( $user_id, "user_pic_url", $content );
 
 
  $ar = array('reg'=>'true','msg'=>'success', "id" => $user_id);
  echo json_encode( $ar );
  exit();
 
 } else {
  $ar = array ("reg" => 'false', 'false' => "registration failed: Sorry, that username already exists!");
  echo json_encode( $ar );
  exit();
 }
} else {
 $ar = array ("reg" => 'false', "msg" => "Require Field Missing");
 echo json_encode( $ar );
 exit();
}
?>