recreate newrelice account and replace the license key
update comment api

* limit time for 4 hour
rename programs column
update program and comment model
update program model test
update program model test
update program model test
update api test
add parent-child relationship for comment

* use postgresql with recurion
update comment model test

* add test for parent-child
* add test of ancestor
update api of comment

* add ancestor for return commetns