Bj/feature/rails template

I've added a file into the root directory called template.rb, which can be used as a Rails template.  To test it locally, try something like this:

```sh
# Get this branch.
git clone git@github.com:adaptivelab/market_sprint_rails_template.git
cd market_sprint_rails_template
git checkout bj/feature/rails_template
cd ..

# Create a new app from the template.
gem install rails -v4.1.0
rails new test_app -m market_sprint_rails_template/template.rb

# Apply the template to an existing app.
cd test_app
bundle exec rake rails:template LOCATION=../market_sprint_rails_template/template.rb
```