fix layer

src/layer/layer.hpp

@@ -1,6 +1,5 @@
 #pragma once
 
-#include <string>
 #include "event/event.hpp"
 #include "utils/using.hpp"
 
@@ -24,7 +23,6 @@ namespace VE
 
     protected:
       event_fn<event> execute;
-      std::string m_key;
   };
 }