Would be nice to have AuthHelpers included

For RSpec 3+

`spec/rails_helper.rb`

```
RSpec.configure do |config|
  config.include AuthHelpers
end
```

`spec/support/auth_helpers.rb`

```
module AuthHelpers
  def sign_in(account)
    allow(@controller).to receive(:authenticate_account!).and_return(true)
    allow(@controller).to receive(:current_account).and_return(account)
  end
end
```
