Control & Promote administrator status via a method rather than a prop

app/Http/Middleware/AdminOnly.php

@@ -16,7 +16,7 @@ class AdminOnly
      */
     public function handle($request, Closure $next)
     {
-        if (! Auth::user()->is_admin) {
+        if (! Auth::user()->isAdministrator()) {
             throw new AuthorizationException;
         }