User Model / Sorcery / Gems / Tests

## Changes in this pull request

### Routes

* Added routes to handle authentication and users

### Controllers

* Added Sessions controller to handle authentication
* Added Home controller to put the home page
* Added User controller to create user

### User Models

* Modified User model to implement sorcery
* Added validations for password and email
* Added migrations to add password (crypted and salt), and remember_me tokens

### Tests

* Added tests to cover the User model
* Configured SimpleCov to ignore /spec and /config

### Gems

* Installed Sorcery
* Installed SimpleCov
* Installed Better Errors
* Installed Bootstrap

### Git Ignore

* Added coverage file to gitignore

### Todo

* Styling