NFR: flag to do the mapping

[cyberhck]

So every single data loader usage will have a mapping thing going on inside, it's basically:

• query the db
• db returns in an order
• initialize a map and populate that map based on id
• traverse through original input ids,
• create a slice in that original order
• return that slice

I feel like since this is exactly the same for every single data loader which deals with db, why not add a flag which will include this as well?