Corrections from parte1 except show comment errors
Add more styling

Conflicts:
	Gemfile
	Gemfile.lock
	app/assets/stylesheets/application.css.scss
	app/views/layouts/_header.html.erb
Add comments validations
Fixed reviews
Merge pull request #1 from mixergtz/correcciones_parte1

Correcciones parte1
Add devise and User model
Add articles relationship to user
Add more styling