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/exercises/serializers.py

@@ -0,0 +1,25 @@
+from rest_framework import serializers
+from .models import Exercise
+
+
+class ExerciseSerializer(serializers.ModelSerializer):
+    category_display = serializers.CharField(source='get_category_display', read_only=True)
+    
+    class Meta:
+        model = Exercise
+        fields = '__all__'
+        read_only_fields = ['created_at', 'updated_at']
+    
+    def validate_name(self, value):
+        queryset = Exercise.objects.filter(name__iexact=value)
+        if self.instance:
+            queryset = queryset.exclude(pk=self.instance.pk)
+        if queryset.exists():
+            raise serializers.ValidationError("Eine Übung mit diesem Namen existiert bereits.")
+        return value
+    
+    def create(self, validated_data):
+        request = self.context.get('request')
+        if request and hasattr(request.user, 'profile') and request.user.profile.club:
+            validated_data['club'] = request.user.profile.club
+        return super().create(validated_data)