Add SSH to production environment

- Add SSH to production environment.
- Fix error message method.
Just brush up the layout in user_pages_spec.rb
Refactor test in user_pages_spec.rb
Add a test for success/failure messages in signup page
Refactor ERb in Application.html.erb
Generate Sessions controller and authentication tests
First implementation in Session controllers/routing
Add implementation of signin failure and its test
First implementation of signin success and session start
Initial implementation of remember_token and db migration
Add a test for remember_token
Add methods for remember token to User model
Second implementation of remember_token
Add current_user method for remember_token
Finish implementation of sign in
Add auto sign-in after sign up
Implement sign out
Add custom matcher and helper method
Refactor session view/controller so that form_tag is used insted of form_for
Reorganize spec support utilities.rb into modules