Updated the Gemfile and config/application.rb for Heroku deploy

These are the standard instructions. Remember to bundle!
Specify Ruby version so Heroku locks in
Adding Gemfile.lock against the .gitignore

Heroku needs to see our Gemfile.lock ; it was getting confused without it.
Merge branch 'heroku_config'
Merge in Gemfile and Config updates for Heroku

Heroku needs a rails12 gem and different precompile settings
Merge pull request #95 from fence-lizards-2014/heroku_config

Heroku config