ASTPP category correction

README.md

@@ -392,7 +392,6 @@ _[IRC](https://en.wikipedia.org/wiki/Internet_Relay_Chat) communication software
 _[SIP](https://en.wikipedia.org/wiki/Session_Initiation_Protocol) telephony software_
 
 - [Asterisk](http://www.asterisk.org/) - Easy to use but advanced IP PBX system, VoIP gateway and conference server. `GPL-2.0` `C`
-- [ASTPP](https://www.astppbilling.org/) - is an Open Source VoIP Billing Solution for Freeswitch. It supports prepaid and postpaid billing with call rating and credit control. It also provides many other features. ([Source Code](https://github.com/iNextrix/ASTPP)) `AGPL-3.0` `PHP`
 - [FreeSWITCH](https://freeswitch.org/) - Scalable open source cross-platform telephony platform. ([Source Code](https://freeswitch.org/stash/projects/FS/repos/freeswitch/browse)) `MPL-2.0` `C`
 - [Homer](https://www.sipcapture.org/) - Troubleshooting and monitoring VoIP calls. ([Source Code](https://github.com/sipcapture/homer)) `AGPL-3.0` `Angular/C`
 - [Kamailio](http://www.kamailio.org/w/) - Modular SIP server (registrar/proxy/router/etc). ([Source Code](https://github.com/kamailio/kamailio)) `GPL-2.0` `C`
@@ -405,6 +404,7 @@ _[SIP](https://en.wikipedia.org/wiki/Session_Initiation_Protocol) telephony soft
 
 _[IPBX](https://en.wikipedia.org/wiki/IP_PBX) telephony software_
 
+- [ASTPP](https://www.astppbilling.org/) - is an Open Source VoIP Billing Solution for Freeswitch. It supports prepaid and postpaid billing with call rating and credit control. It also provides many other features. ([Source Code](https://github.com/iNextrix/ASTPP)) `AGPL-3.0` `PHP`
 - [Freepbx](http://www.freepbx.org) - Web-based open source GUI that controls and manages Asterisk. ([Source Code](http://git.freepbx.org/projects/FREEPBX)) `GPL-2.0` `PHP`
 - [FusionPBX](https://www.fusionpbx.com/) - Open source project that provides a customizable and flexible web interface to the very powerful and highly scalable multi-platform voice switch called FreeSWITCH. ([Source Code](https://github.com/fusionpbx/fusionpbx)) `MPL-1.1` `PHP`
 - [Kazoo](http://2600hz.org/) - KAZOO is an open-source, highly scalable software platform designed to provide carrier-grade VoIP switch functions and features. ([Source Code](https://github.com/2600hz/KAZOO)) `MPL-1.1` `Erlang`