fix

migrate.ts

@@ -85,7 +85,7 @@ async function migrateMatch(match: Match) {
         return;
     }
     let winner_id: string | number;
-    if (typeof(oldMatch.winner_id) === "number") {
+    if (typeof(oldMatch.winner_id) === "number" && oldParticipantIdMap.has(oldMatch.winner_id)) {
         const winnerName = oldParticipantIdMap.get(oldMatch.winner_id as number).name;
         winner_id = newParticipantNameMap.get(winnerName).id;
         console.log(`Migrating match ${currentMatchPlayer1Name} vs ${currentMatchPlayer2Name} with winner ${winnerName}.`);