added geo module, with region supporting gis data

geo/serializers.py

@@ -0,0 +1,68 @@
+from rest_framework import serializers
+
+from . import models
+
+
+class CountryReadSerializer(serializers.ModelSerializer):
+
+    class Meta:
+        model = models.Country
+        fields = '__all__'
+
+
+class CountryWriteSerializer(CustomWriteSerializer):
+
+    class Meta:
+        model = models.Country
+        fields = '__all__'
+
+
+class RegionWriteSerializer(CustomWriteSerializer):
+    country = serializers.IntegerField()
+
+    def validate_country(self, value):
+        return models.Country.objects.using(self.context['db']).filter(id=value).first()
+
+    class Meta:
+        model = models.Region
+        fields = '__all__'
+
+
+class RegionReadSerializer(serializers.ModelSerializer):
+
+    country = CountryReadSerializer()
+
+    class Meta:
+        model = models.Region
+        fields = '__all__'
+
+
+class ProvinceReadSerializer(serializers.ModelSerializer):
+
+    region = RegionReadSerializer()
+
+    class Meta:
+        model = models.Province
+        fields = '__all__'
+
+
+class CityWriteSerializer(CustomWriteSerializer):
+
+    region = serializers.IntegerField()
+
+    def validate_region(self, value):
+        return models.Region.objects.using(self.context['db']).filter(id=value).first()
+
+    class Meta:
+        model = models.City
+        fields = '__all__'
+
+
+class CityReadSerializer(serializers.ModelSerializer):
+
+    province = ProvinceReadSerializer()
+
+    class Meta:
+        model = models.City
+        fields = '__all__'
+