register and sign in pages

backend/locations/serializers.py

@@ -0,0 +1,23 @@
+from rest_framework import serializers
+
+from .models import Atoll, Island
+
+
+class IslandSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Island
+        fields = ["id", "name", "atoll"]
+
+
+class AtollSerializer(serializers.ModelSerializer):
+    """Atolls with their islands nested - the registration form needs both."""
+
+    islands = serializers.SerializerMethodField()
+
+    class Meta:
+        model = Atoll
+        fields = ["id", "name", "code", "islands"]
+
+    def get_islands(self, obj) -> list[dict]:
+        islands = [island for island in obj.islands.all() if island.is_active]
+        return IslandSerializer(islands, many=True).data