config routes and factories for testing authentication
initial features and tests for user authentication
added email to user model
complete refactor for user email field
deleted sessions files from commit
completes basic user authentication

* adds new file session_controller to manage sessions
* adds authenticate class method to User to authenticate password passed through params
* adds create methods to session_controller to set session[:user_id] if passed authentication
* adds current user helper to sessions controller
* checks for current_user on index page
* tests for all above features
Merge pull request #18 from tiger-swallowtails-2013/add_email_to_user

Add email to user