public function up(): void 	{ 		Schema::create('notification_targets', function (Blueprint $table): void { 			$table->uuid('id')->primary(); 			$table->uuid('notification_id'); 			$table->uuid('user_id'); 			$table->dateTime('seen_at')->nullable(); 			$table->timestamps();  			$table->index(Model::CREATED_AT);  			$table->foreign('notification_id')->references('id')->on('notifications')->cascadeOnDelete(); 			$table->foreign('user_id')->references('id')->on('users')->cascadeOnDelete(); 		}); 	}