README.md in motion-kit-0.18.0 vs README.md in motion-kit-1.0.0

@@ -1,13 +1,15 @@
 # MotionKit
 
+[![Join the chat at https://gitter.im/motion-kit/motion-kit](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/motion-kit/motion-kit?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+
 [![Build Status](https://travis-ci.org/motion-kit/motion-kit.svg?branch=master)](https://travis-ci.org/motion-kit/motion-kit)
 [![Version](https://badge.fury.io/rb/motion-kit.svg)](https://rubygems.org/gems/motion-kit)
 
 *The RubyMotion layout and styling gem.*
 
-1. Crossplatform compatibility: iOS, OSX, and planned support for Android
+1. Crossplatform compatibility: iOS, OSX, tvOS and planned support for Android
 2. Simple, easy to learn DSL
 3. Crossframework compatibility:
    - [UIKit][readmore-uikit]
    - [AppKit][readmore-appkit]
    - [AutoLayout][readmore-autolayout]
@@ -856,9 +858,45 @@
 @container_bottom.minus kbd_height  # set @container_bottom.constant = 0 when the keyboard disappears
 
 UIView.animateWithDuration(duration, delay: 0, options: curve, animations: -> do
   self.view.layoutIfNeeded  # applies the constraint change
 end, completion: nil)
+```
+
+You can also activate/deactivate constraints selectively, and animate the
+transitions between them.
+
+```ruby
+class MyLayout < MK::Layout
+
+  def layout
+    add UIButton, :my_button do
+      constraints do
+        @top_constraint = top.equals(:superview, :bottom)
+        @bottom_constraint = bottom.equals(:superview).deactivate
+        left.equals(:superview)
+        right.equals(:superview)
+        height 48
+      end
+  end
+
+  def show_button
+    @top_constraint.deactivate
+    @bottom_constraint.activate
+    UIView.animateWithDuration(0.3, animations: -> do
+      self.view.layoutIfNeeded
+    end)
+  end
+
+  def hide_button
+    @bottom_constraint.deactivate
+    @top_constraint.activate
+    UIView.animateWithDuration(0.3, animations: -> do
+      self.view.layoutIfNeeded
+    end)
+  end
+
+end
 ```
 
 ### MotionKit::Events
 
     gem install motion-kit-events