Update README with Heroku instructions

Author: OrkoHunter

README.md

@@ -64,14 +64,17 @@ Note: Without the GitHub oauth key the number of requests is throttled at 60 per
 Run Redis and Server
 ----------
 
+If you are running locally then run local redis server
+
 ```bash
 $ redis-server
 ```
 
+On heroku, you can set up `Heroku Redis` add-on and it sets `REDIS_URL` enviornment variable.
+
 In a separate window:
 ```bash
 $ node server
 ```
 
 Note: For production run `export NODE_ENV="production"` before starting the server.
-

server/index.js

@@ -11,8 +11,12 @@ var helmet = require('helmet');  // To change response headers
 
 // To temporarily store JSON data from GitHub and also
 // the number of connected users
-var redis = require("redis"),
+var redis = require("redis");
+if (process.env.REDIS_URL) {
     redis_client = redis.createClient(process.env.REDIS_URL);
+} else {
+    redis_client = redis.createClient();
+}
 
 var path = require('path');