title: mongodb text search with multiple fields
body: <p>I'm trying to get mongodb fulltext search with multiple fields working.
  I've set the index on 3 fields-name,description, category, and verified with </p>
  
  <p><code>document.collection.getIndexes ()</code>, 
  which returns-</p>
  
  <pre><code>[
      {
          "v" : 1,
          "key" : {
              "_id" : 1
          },
          "name" : "_id_",
          "ns" : "document.collection"
      },
      {
          "v" : 1,
          "key" : {
              "name" : 2,
              "description" : 1,
              "category" : 1
          },
          "name" : "name_2_description_1_category_1",
          "ns" : "document.collection",
          "background" : true,
          "safe" : null
      }
  ]
  </code></pre>
  
  <p>Now, if I try to perform a text search, using the follwing command-</p>
  
  <pre><code>db.collection.find(  {$text:{$search:'alias'}}  ).limit(10)
  </code></pre>
  
  <p>got the following error message:</p>
  
  <pre><code>error: {
      "$err" : "Unable to execute query: error processing query: ns=document.collection limit=10 skip=0\nTree: TEXT : query=alias, language=, tag=NULL\nSort: {}\nProj: {}\n planner returned error: need exactly one text index for $text query",
      "code" : 17007
  }
  </code></pre>
  
  <p>I tried google and mongodb docs but I couldn't find anything.</p>