Add "Claper" on "platforms" section

README.md

@@ -49,6 +49,7 @@
 
 ## Platforms
 *Conference Managers, Call for Speakers Managers, Ticket Managers, ...*
+- [Claper](https://claper.co/) - The ultimate tool to interact with your audience. An open-source alternative to Slido, AhaSlides and Mentimeter.
 - [PaperCall](https://www.papercall.io/) - PaperCall enables event organizers and speakers to easily manage their call for papers and talk submissions.
 - [Sessionize](https://sessionize.com/) - The smart way to manage Call for Papers, Speakers and Agenda for your conference. Cloud based, safe and easy.
 - [Sli.do](https://www.sli.do/) - Empower your audience to ask questions, vote in polls and be a part of the discussion by using a simple Q&A and polling tool.