Convert to haml

Converted everything to HAML and made sure the index action still works.

Also made a rake task, `rake db:import`, which will load in activities.  I still have some more work to do on it to make it more robust, but it works for now.  You have to make sure you have no Activities in your database and then run the command and it will populate it with whatever info is in the `db/data/activity.yml` file.