title: Design or Plugin suggestion for Wordpress site
body: <p>I need to create a WP site which will have multiple subjects. Each subject will have multiple lessons and each lesson will have meta data like title, description etc etc. A User will be allowed to read some lessons and based on number of lessons read, he will be assigned some custom badges.</p>
  
  <p>While showing any lesson, we should be able to show the list of users who have already read that lesson.</p>
  
  <p>To get this done on WP, I am planning to use some Custom Content Type Plugin which I can use to create Subject, Lessons and the User Meta to store users action on any lesson. The Badges can also be made part of Users Meta.</p>
  
  <p>The Problem I see are</p>
  
  <ol>
  <li>I dont know any way to map Subjects to Lessons i.e while creating a new lesson, I should be able to map it to one subject (like we do node linking in Drupal )</li>
  <li>I am not use if User meta table can be used to store many to many info like "XYZ user have read 25 lessons" and "ABC Lesson was read by 10 Users"</li>
  </ol>
  
  <p>What should be the best design for this kind of Application.</p>