qmk_firmware/keyboards/the_ruler/the_ruler.h

#ifndef THERULER_H
#define THERULER_H

#include "quantum.h"

#define LAYOUT( \
    K00, K01, K02, K03, K04, K05 ) { \
    { K00, K01, K02, K03, K04, K05 }  \
}

#endif