Add remark42 (#1572)

README.md

@@ -442,6 +442,7 @@ _[IPBX](https://en.wikipedia.org/wiki/IP_PBX) telephony software_
 - [phpBB](https://www.phpbb.com/) - Flat-forum bulletin board software solution that can be used to stay in touch with a group of people or can power your entire website. ([Source Code](https://github.com/phpbb/phpbb)) `GPL-2.0` `PHP`
 - [PPnet](https://github.com/pixelpark/ppnet) - Create and host your own social network. `MIT` `Javascript`
 - [Pump.io](http://pump.io/) - Stream server that does most of what people really want from a social network. ([Source Code](https://github.com/e14n/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/remark)) `MIT` `Go`
 - [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`
 - [Socialhome](https://socialhome.network) - Federated and decentralized profile builder and social network engine. ([Demo](https://socialhome.network/public/), [Source Code](https://github.com/jaywink/socialhome)) `AGPL-3.0` `Python`