Update AccountTransformer

app/Transformer/Api/AccountTransformer.php

@@ -33,7 +33,7 @@ class AccountTransformer extends Fractal\TransformerAbstract
 			'website' => $profile->website,
 			'local' => (bool) $local,
 			'is_admin' => (bool) $is_admin,
-			'created_at' => $profile->created_at->timestamp,
+			'created_at' => $profile->created_at->toJSON(),
 			'header_bg' => $profile->header_bg
 		];
 	}