Create Session controller
Add login form in views/sessions/new.html.erb
Support for login with invalid data (flash error message)
Login support with simple user panel in header
Test user login to the application
Add logout possibility with session.delete(:user_id) plus passed tests
Remembering and forgetting users with cookies on log in and log out
Add remember me checkbox in login form and its styling to custom.css.scss
Remember me checkbox working
Test remembering with login users
Finish log-in-log-out branch
Merge branch 'log-in-log-out' into develop

Finish work on log-in-log-out branch
Solve execrises from chapter 8