Fix tournament serializer

apps/participation/api/serializers.py

@@ -53,6 +53,8 @@ class TeamSerializer(serializers.ModelSerializer):
 
 
 class TournamentSerializer(serializers.ModelSerializer):
+    participations = serializers.ListSerializer(child=ParticipationSerializer())
+
     class Meta:
         model = Tournament
         fields = ('name', 'date_start', 'date_end', 'place', 'max_teams', 'price', 'remote',