void CreateDatabase()
{
db = CreateInstance <WordDatabase>();
AssetDatabase.CreateAsset(db, "Assets/" + WordDatabase.db_path);
AssetDatabase.SaveAssets();
AssetDatabase.Refresh();
}
void LoadDatabase()
{
db = AssetDatabase.LoadAssetAtPath <WordDatabase>("Assets/" + WordDatabase.db_path);
if (db == null)
{
CreateDatabase();
}
}