read.scala

  db.readOnly { implicit s =>
    // only reading from db - not in a transaction
  }
  db.readWrite { implicit s =>
    // reading and writing to db in a transaction
  }
  db.readWrite(3) { implicit s =>
    // reading and writing to db in a transaction with retries if a database
    // exception is thrown (up to 3 attempts total) by rolling back the
    // transaction, starting a new one, and re-executing the block.
  }