add Mailspring

README.md

@@ -428,6 +428,7 @@
 - [Hiri](https://www.hiri.com/) - Hiri is a business focused desktop e-mail client for sending and receiving e-mails, managing calendars, contacts, and tasks.
 - [![Open-Source Software][OSS Icon]](https://cgit.kde.org/kmail.git/) [KMail](https://www.kde.org/applications/internet/kmail/) - KMail is the email component of Kontact, the integrated personal information manager from KDE.
 - [![Open-Source Software][OSS Icon]](https://github.com/pulb/mailnag) [Mailnag](https://launchpad.net/~pulb/+archive/ubuntu/mailnag) - Mailnag is a daemon program that checks POP3 and IMAP servers for new mail.
+- [![Open-Source Software][OSS Icon]](https://github.com/Foundry376/Mailspring) [Mailspring](https://getmailspring.com/) - A beautiful, fast and maintained fork of @Nylas Mail by one of the original authors.
 - [![Open-Source Software][OSS Icon]](https://github.com/nylas/nylas-mail) [Nylas Mail](https://www.nylas.com/download) - An extensible desktop mail app built on the modern web.
 - [![Open-Source Software][OSS Icon]](http://sylpheed.sraoss.jp/en/download.html#stable) [Sylpheed](http://sylpheed.sraoss.jp/en/) - Lightweight and user-friendly e-mail client.
 - [![Open-Source Software][OSS Icon]](https://releases.mozilla.org/pub/thunderbird/) [Thunderbird](https://www.mozilla.org/en-US/thunderbird/) - Thunderbird is a free email application that’s easy to set up and customize and it’s loaded with great features.