title: how to create binary index with ruby on rails active record?
body: <p>My 'Actions' table contains some discrete values fields : Status, Priority, Mode. (I work with Postgres, Oracle, MSSQL databases).</p>
  
  <p>I'd like to be able to sort out Actions based on theses fields, so I think of using a bitmap index.
  I can't find the syntax for this type of indexes in Rails guides.</p>
  
  <p>Can someone give me a hint? </p>
  
  <p>Thanks!</p>