Simple patch to allow references to other fixture data

Here's another simple patch that allows you to try up fixtures:

It also includes tests and rdoc. Basically, in a fixture, you can say

   id: 2
   account_id: <%= fixture :accounts, :elevatedrails%>

And that will grab the value from another fixture. It is dead simple and helps clean up fixtures.

Can we get this one applied as well?


Hey, yeah. This is a good solution to the fixture join problem, I think.



  > id: 2
  > account_id: <%= fixture :accounts, :elevatedrails%>

The fixture_reference plugin reuses a syntax we already know in Rails:

  <%= fixtures :accounts %>
     id: 2
     account_id: <%= accounts(:elevatedrails) %>

I find that more readable.