This app is a small server to serve as a GitHub Post-Receive hook to add 
comments, and update state in Pivotal Tracker, similar to say the Lighthouse
service integration.
Configure your Tracker API key, and Project ID in a config.yml file placed in 
the same directory as this app.  It should look something like:
tracker_github_hook:
  github_url: 'https://github.com/chris/tracker_github_hook'
  tracker_api_token: a1230e72340e3babc96d5e2fab67c18d
  tracker_project_id: 123
  
The label ('tracker_github_hook' in this case) is arbitrary and not used, it's
just their to be a useful bit of info to humans/organize the nested settings, 
and is not used.  This setup allows you to have one service that supports
multiple Tracker/GitHub projects, just define one of the above blocks for each
one, and then anytime GitHub sends a push, the service will tease out which
GitHub repo it came from and correlate that to which Tracker project you've
assigned to that.
When you make commits to Git/GitHub, and want a comment and optionally a state 
update made to a story in Tracker, add the following text to your commit 
message:
    
    [Story#####]
    
or
    [Story##### state:finished]
where ##### is the story number (see the bottom of an expanded story in 
Tracker for its ID).
This project also requires the following rubygems:
- sinatra
- rest-client
- json
More information for, and thanks to:
Pivotal Tracker API: https://www.pivotaltracker.com/help/api
GitHub Post-Receive Hooks: https://github.com/guides/post-receive-hooks
Sinatra: https://sinatra.rubyforge.org/
RestClient: https://rubyforge.org/projects/rest-client/
TODO:
- cleanup, better testing
- support other story changes, like assigned user, etc.