Authenticate user

* log in
* log out
* current_user
Add ROLES, user controller and authorization

* views to create new users
* authorization by role
Renders different new view depending on role
Fix warnings stubbing current_user
Fix travis db:migrate
Fix typo in .travis.yml
User uses has_secure_password

* ROLES from hash to array
* (User) role method returns a symbol
Refactoring move some file to admin directory.
WIP: Refactoring permissions

* Controller template_render not passing
Refactoring move users_controller_spec to admin directory
Fix Users Controller testing
Add remember_me and reset password
Add testing and some fixes
Refactoring RSpec

* remove factory_girl.rb
* add factorygirl configuration to rails_helper.rb
* remove require rails_helper from spec files
* add require rails_helper to .rspec
Remove blank extra line in users_controller.rb
Merge pull request #3 from d2bit/authentication

Authentication