Document layout guide properties

Author: Baris Sencan

README.md

@@ -31,8 +31,6 @@ Just `import ManualLayout` in your code and use the methods and properties provi
 
 #API Cheat Sheet
 
-Properties provide a simple layout API while methods provide a more powerful one.
-
 ###CALayer/UIView Properties
 
 ```swift
@@ -64,6 +62,13 @@ The difference between alternate edges and normal edges require a bit of explain
 
 So basically, *setting a normal edge's position drags the whole view along with that edge but setting an alternative edge's position drags just that edge*. And don't worry if you, for example, try to drag a left edge past its view's right edge. Edge swapping is done automatically so you don't have to worry about.
 
+###UIViewController Properties
+
+```swift
+var top: CGFloat // Top layout guide y coordinate. Read-only.
+var bottom: CGFloat // Bottom layout guide y coordinate. Read-only.
+```
+
 ###CALayer/UIView Methods
 
 Replace the word "layer" with "view" for the UIView methods.