adding devise on the Le Wagon minimal template with 2 models
Created by: SGALT
Installation of devise on the Le Wagon minimal template. Setting of _flashes.html.erb on a shared folder. Setting of the prerequisite for the devise installation on the rails app. Creation of Hotel and Room models with devise with the minimum fields for now. Migration of the models. Rails generate of the views for the 2 models. Activation of the authentication for the 2 models on the white-list model. Small and quick tests on localhost.