title: greenDao Schema Upgrade
body: <p>I have seen another question about schema upgrade/migration using green dao (<a href="https://stackoverflow.com/questions/13373170/greendao-schema-update-and-data-migration">here</a>)</p>
  
  <p>There are lots of links in that answer for a good pattern to use when doing schema upgrades - however there are no examples of what you actually do to your data to migrate it properly and I'm having trouble finding anything.  </p>
  
  <p>In my case, my migration is incredibly straight forward - I do not wish to transform any existing data, I simply need to add some new tables to my schema, which I suspect is a fairly common situation.</p>
  
  <p><strong>What is the easiest way to add new tables to your schema without deleting data your users have already saved?  A specific example would be greatly appreciated.</strong></p>
  
  <p>It would be awesome if greenDao provided a class similar to DevOpenHelper that would simply add new tables/columns that didn't previously exist in the schema without dropping existing tabes/data first.</p>