add new struct and events

example/main.cpp

@@ -0,0 +1,21 @@
+#include "layers/ui_layer/ui_layer.hpp"
+
+namespace sandbox
+{
+  class app : public VE::application
+  {
+    public:
+      app(std::string app_name) : VE::application{ app_name } {};
+      ~app() = default;
+  };
+}
+
+auto main(int argc, char* args[]) -> int
+{
+  sandbox::app app{ "vertex_engine_sandbox" };
+
+  app.push_layer(
+    new sandbox::ui_layer{}
+  );
+  app.run();
+}