Added details on mock interviews.

Author: jwasham

README.md

@@ -1415,9 +1415,9 @@ Challenge repos:
 - [Interactive Coding Interview Challenges in Python](https://github.com/donnemartin/interactive-coding-challenges)
 
 Mock Interviews:
-- [Gainlo.co: Mock interviewers from big companies](http://www.gainlo.co/)
-- [Pramp: Mock interviews from/with peers](https://www.pramp.com/)
-- [Refdash: Mock interviews](https://refdash.com/)
+- [Gainlo.co: Mock interviewers from big companies](http://www.gainlo.co/) - I used this and it helped me relax for the phone screen and on-site interview.
+- [Pramp: Mock interviews from/with peers](https://www.pramp.com/) - peer-to-peer model of practice interviews
+- [Refdash: Mock interviews and expedited interviews](https://refdash.com/) - also help candidates fast track by skipping multiple interviews with tech companies.
 
 ## Once you're closer to the interview