Metadata.expires_atをCarbon化

app/Metadata.php

@@ -12,4 +12,6 @@ class Metadata extends Model
 
     protected $fillable = ['url', 'title', 'description', 'image', 'expires_at'];
     protected $visible = ['url', 'title', 'description', 'image', 'expires_at'];
+
+    protected $dates = ['created_at', 'updated_at', 'expires_at'];
 }