feat: add CurriculumSerializer

backend/flashcards/serializer.py

@@ -0,0 +1,14 @@
+# serializers.py in your Django app
+from rest_framework import serializers
+
+
+class CurriculumSerializer(serializers.Serializer):
+    curriculum = serializers.ListField(
+        child=serializers.FileField(allow_empty_file=False, use_url=False),
+    )
+
+    def validate_curriculum(self, value):
+        # Check minimum number of files
+        if len(value) < 1:
+            raise serializers.ValidationError("At least one file must be uploaded.")
+        return value