Add gems
Add user model
Add users controller & routes
Add view for users
Add bootsrap in manifest & style.css
Add sessions controler and view
Add sessions routes
Fix redirect after user create
Fix sign_up link path
Fix gemfile
Update layout
Add header partial for layout
Remove custom validator file
Add root path
Fix link in header
Commented default value for name, add presence validation
Add callback in user controller
Add erorrs in view
Add form partial, Edit user page
Fix view if user sign_in