Introduction devise create user form in issues index
* Generate devise views
* New user form transfered to a partial
Visibility restrictions
* Each user can only see his issues
* New session form transfered to a partial and rendered in issues index
* Change id and class of new session form
Modifiying routes
* Change default routes after sing_in, sign_up and sign_out
* Update of tests after necessary sign in to see the issus opened and received
* Generate devise controllers (needed for change after sign_up default route)
Comments page is working now
* Refactor of index method in issues controller
* Put the log_out link only for loged in users in issues_controller index
* Add issues references and body field to comments
* Comment pry debugger gems because interfered with some keys in pry console
* TDD to create comments page. New comment form is working with ajax