feat: Add flag URL to Country type and update CountryCard component

backend/server/worldtravel/serializers.py

@@ -1,13 +1,24 @@
+import os
 from .models import Country, Region, VisitedRegion
 from rest_framework import serializers
 
 
 class CountrySerializer(serializers.ModelSerializer):
+    def get_public_url(self, obj):
+        return os.environ.get('PUBLIC_URL', 'http://127.0.0.1:8000').rstrip('/')
+
+    flag_url = serializers.SerializerMethodField()
+
+    def get_flag_url(self, obj):
+        public_url = self.get_public_url(obj)
+        return public_url + '/media/' + 'flags/' + obj.country_code + '.png'
+
     class Meta:
         model = Country
         fields = '__all__'  # Serialize all fields of the Adventure model
 
 class RegionSerializer(serializers.ModelSerializer):
+    flag_url = ''
     class Meta:
         model = Region
         fields = '__all__'  # Serialize all fields of the Adventure model