Update readme.md

Author: johndatserakis

readme.md

@@ -80,6 +80,9 @@ knex seed:make seed_users
 
 ```
 
+#### Note
+You'll need to make sure you have redis running (for the rate-limiter). I use homebrew. You can follow [this](https://medium.com/@petehouston/install-and-config-redis-on-mac-os-x-via-homebrew-eb8df9a4f298) guide. After installing and running redis, you should be able to enter `redis-cli ping` into a terminal and get `PONG` back.
+
 ## General Information
 
 This backend is part of a pair of projects that serve a simple notes app. I chose a notes app because it gives you a good look at the different techniques used in both the frontend and backend world. What's really cool is these projects feature a fully fleshed-out user login/signup/forgot/reset authentication system using JWT.