title: How do I reindex a collection using Mongoid?
body: <p>Mongoid provides a few rake tasks, one of which creates the indexes for all collections in the database:</p>
  
  <p>rake db:create_indexes</p>
  
  <p>But correct me if I'm wrong, isn't creating indexes different than actually indexing all of the items?  How can I go about reindexing my documents?  This would be necessary if I added an index to a new collection in Rails but already have 10,000 items in the database.</p>