code: function databaseInitialize() {
    var entries = db.getCollection("entries");
    var messages = db.getCollection("messages");
  
    // Add our main example collection if this is first run.
    // This collection will save into a partition named quickstart3.db.0 (collection 0)  
    if (entries === null) {
      // first time run so add and configure collection with some arbitrary options
      entries = db.addCollection("entries");
    }
  
    if (messages === null) {
      messages = db.addCollection("messages");
      messages.insert({ txt: "i will only insert into this collection during databaseInitialize" });
    }
  }
docs: set up an initialize function for first load (when db hasn't been created yet)