code: func newDB(c *Context) (*empire.DB, error) {
  	db, err := empire.OpenDB(c.String(FlagDB))
  	if err != nil {
  		return nil, err
  	}
  
  	db.Schema = &empire.Schema{
  		InstancePortPool: &empire.InstancePortPool{
  			Start: uint(c.Int(FlagInstancePortPoolStart)),
  			End:   uint(c.Int(FlagInstancePortPoolEnd)),
  		},
  	}
  
  	return db, nil
  }
docs: // DB ===================================