Merge pull request #24 from calebkleveter/draft

Added Micro-tutorial and Example

week4-18-02-19.md

@@ -158,8 +158,19 @@ The community has been coming up with all sorts of useful extensions to core Vap
 ## Microtutorial
 Standard promise chains are perfectly fine if only one `Future` needs to complete before you can move onto the next step, but what if you need the results from two `Future`s? One of the problems run into here is that you often need to start embedding promise callbacks and all of a sudden you're back to callback hell. 
 
+Let's say you have a route that creates a `User`. That user has some metadata that is connected to it, but you store it in a different database table to normalize your database. You need to create a `Pivot` so you can get the user's metadata. Because a pivot is based on the models ID's, both the models have to be saved in the database first. To make sure the models are saved before you create the pivot, you can use `Async`'s global `flatMap` method, which takes in a return type, and two or three futures. There is then a completion handler that passes in the results of the futures where you can create your pivot:
+
+```swift
+let user = // Create user here
+let metadata = // Create metadata
+flatMap(to: User.self, user.save(on: request), metadata.save(on: request)) { user, metadata in
+    return UserMetadata(user, metadata).save(on: request).transform(to: user)
+}
+```
+
 ***
 ## Credits:
 [@twof](https://github.com/twof)  
 [@Cellane](https://github.com/Cellane)  
 [@bensyverson](https://github.com/bensyverson)
+[@calebkleveter](https://github.com/calebkleveter)