title: ActiveRecord class association
body: <p>Let's pretend that we have two tables, Posts and Categories, that have a many to one relationship, one category to many posts. Which would be the best way to go about defining that in the class definitions?</p>
  
  <ol>
  <li>Just Category { has_many Posts }</li>
  <li>Just Post { belongs_to Category }</li>
  <li>Both Category { has_many Posts } AND Post { belongs_to Category }</li>
  </ol>