Adding coverart id field to Song dto object to return the coverart id that the song is associated with so it is easier to get the cover art

include/dto/SongDto.hpp

@@ -23,6 +23,7 @@ namespace dto
         DTO_FIELD(Int32, disc);
         DTO_FIELD(Int32, year);
         DTO_FIELD(Int32, duration);
+        DTO_FIELD(Int32, coverart_id);
     };
 
     #include OATPP_CODEGEN_END(DTO)

include/dto/conversion/DtoConversions.h

@@ -13,6 +13,8 @@ namespace dto { namespace conversion {
         static dto::RegisterResultDto::ObjectWrapper toRegisterResultDto(
             const model::RegisterResult&);
 
+        static dto::SongDto::ObjectWrapper toSongDto(const model::Song&);
+
         static model::Song toSong(dto::SongDto::ObjectWrapper&);
 
         static model::User toUser(dto::UserDto::ObjectWrapper&);