title: Searching issue with the rails-sunspot gem
body: <p>I'm very new to Solr and the Rails Sunspot gem, but it looks very promising for complex searching on a big database.</p>
  
  <p>What I'm trying to do is allow a model in my rails app to be searched on a few fulltext columns and then a collection of its "filters" (which are just a has_and_belongs_to_many association of names).</p>
  
  <p>I tried setting up my model search block as follows</p>
  
  <pre><code>self.searchable do
    text :name, :boost =&gt; 5
    text :description, :instructions
    text :filters do
      filters.map(&amp;:name)
    end
  end
  </code></pre>
  
  <p>And my controller looks like so:</p>
  
  <pre><code>@search = ModelName.search do
    keywords params[:q].to_s
  end
  </code></pre>
  
  <p>However, I cannot seem to produce any results based on keywords found in the filters association. Am I doing something wrong? This is all very new to me.</p>