How to add plugins into eclipse?

There are several methods. The best one, I think is to create an update site. This is explained here: https://rsjazz.wordpress.com/2014/12/03/creating-custom-link-types-for-rational-team-concert/ in section Prepare to Deploy. Another one is explained in https://jazz.net/library/article/1000 last lab.

This is not really an RTC, but an Eclipse and Eclipse extensions related work and there is a lot of information about it available in the Eclipse project on the web and in books about extending Eclipse that you can purchase.