Add a Heroku button!

README.md

@@ -26,8 +26,14 @@ To try Charted out, simply download the repo and run `npm install`
 to install dependencies. After that you will be able to run
 `npm start`. This will start a server at localhost:3000.
 
+### On Heroku
+
+[![Deploy](https://www.herokucdn.com/deploy/button.png)](https://heroku.com/deploy?template=https://github.com/mikesall/charted)
+
+### With Docker
+
 You can also run Charted via _docker_ by running
 `docker build -t charted .` in the repo to build the container. You
-will them be able to run the container using
-`docker run -p 3000:3000 charted`. Server will be accessible at 
+will then be able to run the container using
+`docker run -p 3000:3000 charted`. Server will be accessible at
 localhost:3000

app.json

@@ -0,0 +1,6 @@
+{
+  "name": "charted",
+  "description": "A charting library from Medium",
+  "repository": "https://github.com/mikesall/charted",
+  "keywords": ["node", "express", "static", "charts"]
+}

index.js

@@ -27,7 +27,7 @@ app.get('/get', function (req, res) {
 
 app.use(express.static('pub'))
 
-var server = app.listen(3000, function () {
+var server = app.listen(process.env.PORT || 3000, function () {
   var host = server.address().address
   var port = server.address().port