Initial commit: WrestleDesk full project

- Django backend with DRF (clubs, wrestlers, trainers, exercises, templates, trainings, homework, locations, leistungstest)
- Next.js 16 frontend with React, Shadcn UI, Tailwind
- JWT authentication
- Full CRUD for all entities
- Calendar view for trainings
- Homework management system
- Leistungstest tracking

backend/clubs/serializers.py

@@ -0,0 +1,14 @@
+from rest_framework import serializers
+from .models import Club
+
+
+class ClubSerializer(serializers.ModelSerializer):
+    wrestler_count = serializers.SerializerMethodField()
+    
+    class Meta:
+        model = Club
+        fields = '__all__'
+        read_only_fields = ['created_at', 'updated_at']
+    
+    def get_wrestler_count(self, obj):
+        return obj.wrestlers.filter(is_active=True).count()