Initial setup, review the added gems and their github repositories for more details

- added haml, id should be used for all views, layouts, partials
- added home controller with index action as root path
- added devise for authentication
- added cancancan for authorization
  - current roles admin and trainer; if none is specified the user is considered a client
- added letter_opener to handle user emails during development
- added gmaps4rails, demo usage is shown in home/index