update txt rec

JSON_TEMPLATE.md

@@ -7,6 +7,7 @@ Please follow the template given here or your pull request will not be accepted
 ## To add define which record you want to add, add the type field to the json. Currently supported records: CNAME, A, TXT, MX
 
 ** For MX records, you do not need to put in priority, as it is preset in the system.
+** For TXT records, put your contents into the url field
 
 ## Template:
 ```