/** First creates a record for each of the matches in this round before creating the round. */
@Override
public ContentValues toContentValues(LeagueRound round, ElifutPersistenceService service) {
return ContentValuesBuilder.create()
.put("round_number", round.roundNumber())
.put("matches", TextUtils.join(",", Lists.transform(round.matches(), service::create)))
.build();
}
