Duplicated entry

Postal is duplicated in "complete solutions" and "mailing lists and newsletters" but it is actually only a Sendgrid/Mailgun clone, so it doesn't belong in complete solutions.

README.md

@@ -303,7 +303,6 @@ _Simple deployment of a mail server, e.g. for inexperienced or impatient admins.
 - [Mailu](https://mailu.io/) - Mailu is a simple yet full-featured mail server as a set of Docker images. ([Demo](https://github.com/Mailu/Mailu/wiki/Demo-server), [Source Code](https://github.com/Mailu/Mailu)) `MIT` `Docker/Python`
 - [Mail-in-a-Box](https://mailinabox.email/) - Turns any Ubuntu server into a fully functional mail server with one command. ([Source Code](https://github.com/mail-in-a-box/mailinabox)) `CC0-1.0` `Shell`
 - [Modoboa](http://modoboa.org/en/) - Modoboa is a mail hosting and management platform including a modern and simplified Web User Interface. ([Source Code](https://github.com/tonioo/modoboa)) `MIT` `Python`
-- [Postal](https://github.com/atech/postal) - Postal is a complete and full featured mail server for use by websites and web servers. `MIT` `Ruby`
 - [Qmailtoaster](http://www.qmailtoaster.com/) - Stable, full-featured, easy-to-install mail server based on qmail. ([Source Code](https://github.com/QMailToaster/)) `Multiple` `Linux`
 - [Simple NixOS Mailserver](https://github.com/r-raymond/nixos-mailserver) - A complete mailserver solution leveraging the Nix Ecosystem. `GPL-3.0` `Nix`
 
@@ -342,7 +341,7 @@ _Mailing lists servers and mass mailing software - one message to many recipient
 - [MailyHerald](http://mailyherald.org/) - Self-hosted Mailchimp alternative that you can easily integrate with your site. Helps you send and manage your application mailings. It support email marketing and conducting the daily stream of notifications you send to your users. ([Source Code](https://github.com/Sology/maily_herald)) `LGPL-3.0` `Ruby`
 - [Mautic](https://www.mautic.org/) - Mautic is marketing automation software (email, social and more). ([Source Code](https://github.com/mautic/mautic)) `GPL-3.0` `PHP`
 - [phpList](https://phplist.org) - Newsletter and email marketing with advanced management of subscribers, bounces, and plugins. ([Source Code](https://github.com/phpList/)) `AGPL-3.0` `PHP`
-- [postal](https://github.com/atech/postal) - Fully featured open source mail delivery platform for incoming and outgoing e-mail. `MIT` `Ruby`
+- [Postal](https://github.com/atech/postal) - Fully featured open source mail delivery platform for incoming and outgoing e-mail. `MIT` `Ruby`
 - [Schleuder](https://schleuder.nadir.org/) - GPG-enabled mailing list manager with resending-capabilities. ([Source Code](https://0xacab.org/schleuder/schleuder/tree/master)) `GPL-3.0` `Ruby`
 - [Sympa](https://www.sympa.org/) - Mailing list manager. `GPL-2.0` `Perl`