Replace hardcoded domains with primary domain setting

app/controllers/admin/users_controller.rb

@@ -4,7 +4,7 @@ class Admin::UsersController < Admin::BaseController
 
   def index
     ldap   = LdapService.new
-    @ou    = params[:ou] || "kosmos.org"
+    @ou    = params[:ou] || Setting.primary_domain
     @orgs  = ldap.fetch_organizations
     @pagy, @users = pagy(User.where(ou: @ou).order(cn: :asc))