* validation goes in model:

class Post < ActiveRecord::Base
  validates_presence_of :name, :title
  validates_length_of :title, :minimum => 5
end

* scaffold generates :resource which has a default add/delete model form
* <%=h post.name %> means "sanitize post.name for HTML output"
* edit_<model>_path links to rails' :resource edit for that model
* form_for block to create a form
