Rails 101

Create app (named blog);

$rails new <app name>
$rails new blog

Create database;

$rake db:create

Fire up the rails server

rails server

Generate index (home) page & remove the temporary pre-built page

$rails generate controller home index
$rm public/index.html

Generate resource (modal) – representing a single object – eg. Car / Post / House

$rails generate scaffold <Modal name> <fields>
$rails generate scaffold Post name:string title:string content:text

Do the DB Migration

$rake db:migrate

Rails Console;

$rails console
p = Post.new(:title => "abcd")
p.save
(expecting not to save)
Show the errors created
p.errors 
p.title = "abcdefg"
p.save
(expecting false - aka not saved)
Show errors
p.errors

Reference;

Routes file is: config/routes.rb
Views: app/views
Controllers: app/controllers
DB Migrations db/migrate/<datestamp>_create_<modal name>.rb

Thanks to: http://guides.rubyonrails.org/getting_started.html#getting-up-and-running-quickly-with-scaffolding