Heroku, if you're not already familiar with it, is a Platform-as-a-Service (PaaS) that makes it really easy to deploy your apps online. There are other similar solutions out there, but Heroku was among the first and is currently the most popular. Not only does it make a developer's life easier, but I find that having Heroku deployment in mind when building an app forces you to follow modern app development best practices.
Assuming that you have an account (sign up if you don't), let's install the Heroku Client for the command-line. Heroku offers a Mac OS X installer, the Heroku Toolbelt, that includes the client. But for these kind of tools, I prefer using Homebrew. It allows us to keep better track of what we have installed. Luckily for us, Homebrew includes a heroku-toolbelt formula:
$ brew install heroku-toolbelt
The formula might not have the latest version of the Heroku Client, which is updated pretty often. Let's update it now:
$ heroku update
Don't be afraid to run heroku update every now and then to always have the most recent version.
Login to your Heroku account using your email and password:
$ heroku login
If this is a new account, and since you don't already have a public SSH key in your ~/.ssh directory, it will offer to create one for you. Say yes! It will also upload the key to your Heroku account, which will allow you to deploy apps from this computer.
If it didn't offer create the SSH key for you (i.e. your Heroku account already has SSH keys associated with it), you can do so manually by running:
$ mkdir ~/.ssh
$ ssh-keygen -t rsa
Keep the default file name and skip the passphrase by just hitting Enter both times. Then, add the key to your Heroku account:
$ heroku keys:add
Once the key business is done, you're ready to deploy apps! Heroku has a great Getting Started guide, so I'll let you refer to that (the one linked here is for Python, but there is one for every popular language). Heroku uses Git to push code for deployment, so make sure your app is under Git version control. A quick cheat sheet (if you've used Heroku before):
$ cd myapp/
$ heroku create myapp
$ git push heroku master
$ heroku ps
$ heroku logs -t
The Heroku Dev Center is full of great resources, so be sure to check it out!