text: CREATE TABLE IF NOT EXISTS "WorldDirectory" (
  	`world_id`	BLOB NOT NULL,
  	`name`	TEXT NOT NULL UNIQUE,
  	`hostport`	TEXT NOT NULL,
  
    /* optional */
    `creation_time_usec` INTEGER,
    `last_hearbeat_usec` INTEGER,
  
  	PRIMARY KEY(`world_id`)
  );
  
  INSERT INTO "WorldDirectory" 
  VALUES ("123-456-789", "world1", "localhost:8080"),
         ("123-456-123", "world2", "localhost:8080");
  
  
  world
    id
    name
    hostport
    creation_time_usec
    last_hearbeat_usec
  
  