social.install

<?php
/**
 * @file
 * Install, update and uninstall functions for the social installation profile.
 */

use Drupal\user\Entity\User;
use Drupal\user\Entity\Role;

/**
 * Implements hook_install().
 *
 * Perform actions to set up the site for this profile.
 *
 * @see system_install()
 */
function social_install() {
  \Drupal::configFactory()
    ->getEditable('system.site')
    ->set('page.front', '/stream')
    ->save(TRUE);

  // Assign user 1 the "administrator" role.
  $user = User::load(1);
  $user->roles[] = 'administrator';
  $user->save();

  // Create the content manager role.
  $data = array('id' => 'contentmanager', 'label' => 'Content manager');
  $role = Role::create($data);
  $role->save();

  // Create the site manager role.
  $data = array('id' => 'sitemanager', 'label' => 'Site manager');
  $role = Role::create($data);
  $role->save();

}