Add findOneById to MongoShell's DB collection

find_one_by_id.js

/**************************************************************************** 
* Add this snippet to ~/.mongorc in order to load it to any shell initiated 
* Usage:
*       db.myCollection.findOneById("5149cdbb62d5cbb22c000024")
*       db.myCollection.findOneById("5149cdbb62d5cbb22c000024",{"field":1})
*****************************************************************************/

DBCollection.prototype.findOneById = function(objId ,fields, options ){
	return this.findOne({"_id":ObjectId(objId)}, fields, options);
}