added more data types to CustomField struct

snipcart/common.go

@@ -39,4 +39,7 @@ type Client struct {
 type CustomField struct {
 	Name     string   `json:"name"`
 	Value    string   `json:"value"`
+	Type     string   `json:"type,omitempty"`
+	Options  []string `json:"options,omitempty"`
+	Required bool     `json:"required"`
 }