Add Retrospring to Communication - Social Networks and Forums (#3446)

README.md

@@ -561,6 +561,7 @@ Simple deployment of [E-mail](https://en.wikipedia.org/wiki/Email) servers, e.g.
 - [Pleroma](https://pleroma.social) - Federated microblogging server, Mastodon, GNU social, & ActivityPub compatible. ([Source Code](https://git.pleroma.social/pleroma/pleroma)) `AGPL-3.0` `Elixir`
 - [Pump.io](http://pump.io/) - Stream server that does most of what people really want from a social network. ([Source Code](https://github.com/pump-io/pump.io)) `Apache-2.0` `Nodejs`
 - [remark42](https://remark42.com/) - A lightweight and simple comment engine, which doesn't spy on users. It can be embedded into blogs, articles or any other place where readers add comments. ([Demo](https://remark42.com/demo/), [Source Code](https://github.com/umputun/remark42)) `MIT` `Go`
+- [Retrospring](https://github.com/retrospring/retrospring) - A free, open-source social network following the Q/A (question and answer) principle of sites like Formspring, ask.fm or CuriousCat. ([Demo](https://retrospring.net)) `AGPL-3.0` `Ruby/Nodejs`
 - [schnack](https://github.com/schn4ck/schnack) - Schnack is simple self-hosted node app for Disqus-like drop-in commenting on static websites. `LIL-1.0` `Nodejs`
 - [Scoold](https://scoold.com) - Stack Overflow in a JAR. An enterprise-ready Q&A platform with full-text search, SAML, LDAP integration and social login support. ([Demo](https://live.scoold.com), [Source Code](https://github.com/Erudika/scoold)) `Apache-2.0` `Java`
 - [Simple Machines Forum](https://www.simplemachines.org/) - Free, professional grade software package that allows you to set up your own online community within minutes. ([Source Code](https://github.com/SimpleMachines/SMF2.1)) `BSD-3-Clause` `PHP`