title: Does a good framework for MongoDB "schema" upgrades in Scala exist?
body: <p>What are the options for MongoDB schema migrations/upgrades?</p>
  
  <p>We (my colleagues and I) have a somewhat large (~100 million record) MongoDB collection. This collection is mapped (ORM'd) to a Scala lift-mongodb object that has been through a number of different iterations. We've got all sorts of code in there which handles missing fields, renames, removals, migrations, etc.</p>
  
  <p>As much as the whole "schema-less" thing can be nice and flexible, in this case it's causing a lot of code clutter as our object continues to evolve. Continuing down this "flexible object" path is simply not sustainable.</p>
  
  <p>How have you guys implemented schema migrations/upgrades in MongoDB with Scala? Does a framework for this exist? I know that Foursquare uses Scala with MongoDB and Rogue (their own query DSL)... does anyone know how they handle their migrations?</p>
  
  <p>Thank you.</p>