title: How to work with elasticsearch and associations between index objects?
body: <p>I am using the Tire gem for Rails and a couple of questions have been raised about model associations. How do you work with them? Let say you have a relation between a Person and a car. Each Person have many Cars. Now if you want to index the car objects too, how do you do that? How can you retrieve a person by searching for car.make for example?</p>
  
  <p>In general, I can see that elasticsearch which is document centric doesn't have the same concepts that RDBMS have. One-to-one, one-to-many and many-to-many.</p>
  
  <p>If you have a many-to-many relationship for instance and you want only objects with a property of the other end of the relationship that will be impossible? Is elastic search a better fit with a NoSQL database like MongoDB?</p>