fix: fixed zero tax rate issue by adding custom field
diff --git a/erpnext/regional/south_africa/setup.py b/erpnext/regional/south_africa/setup.py
index a4335bd..ac783b8 100644
--- a/erpnext/regional/south_africa/setup.py
+++ b/erpnext/regional/south_africa/setup.py
@@ -4,11 +4,28 @@
 from __future__ import unicode_literals
 
 # import frappe, os, json
+from frappe.custom.doctype.custom_field.custom_field import create_custom_fields
 from frappe.permissions import add_permission, update_permission_property
 
 def setup(company=None, patch=True):
 	add_permissions()
 
+def make_custom_fields(update=True):
+	is_zero_rated = dict(fieldname='is_zero_rated', label='Is Zero Rated',
+		fieldtype='Check', fetch_from='item_code.is_zero_rated',
+		insert_after='description', print_hide=1)
+	custom_fields = {
+		'Item': [
+			dict(fieldname='is_zero_rated', label='Is Zero Rated',
+				fieldtype='Check', insert_after='item_group',
+				print_hide=1)
+		],
+		'Sales Invoice Item': is_zero_rated,
+		'Purchase Invoice Item': is_zero_rated
+	}
+	
+	create_custom_fields(custom_fields, update=update)
+
 def add_permissions():
 	"""Add Permissions for South Africa VAT Settings and South Africa VAT Account"""
 	for doctype in ('South Africa VAT Settings', 'South Africa VAT Account'):