bugs and push notification for create task

guardian/serializers.py

@@ -169,6 +169,14 @@ class TaskSerializer(serializers.ModelSerializer):
         """Meta info"""
         model = JuniorTask
         fields = ['id', 'task_name','task_description','points', 'due_date', 'junior', 'default_image']
+
+    def validate_due_date(self, value):
+        """validation on due date"""
+        if value < datetime.today().date():
+            raise serializers.ValidationError({"details": ERROR_CODE['2046'],
+                                               "code": 400, "status": "failed",
+                                               })
+        return value
     def create(self, validated_data):
         """create default task image data"""
         validated_data['guardian'] = Guardian.objects.filter(user=self.context['user']).last()