build sys, free, delete

inc/kv.h

@@ -19,5 +19,7 @@ typedef struct
 kv_t *kv_init(size_t capacity);
 int kv_put(kv_t *db, char *key, char *val);
 char *kv_get(kv_t *db, char *key);
+int kv_delete(kv_t *db, char *key);
+int kv_free(kv_t *db);
 
 #endif