Add initial README.md content.

Summary: Closes #1

Reviewers: markwei, O2 Material Motion, appsforartists

Reviewed By: markwei, O2 Material Motion, appsforartists

Subscribers: appsforartists

Tags: #material_motion

Differential Revision: http://codereview.cc/D1839

README.md

@@ -3,6 +3,36 @@
 [![Build Status](https://travis-ci.org/material-motion/material-motion-family-direct-manipulation-swift.svg?branch=develop)](https://travis-ci.org/material-motion/material-motion-family-direct-manipulation-swift)
 [![codecov](https://codecov.io/gh/material-motion/material-motion-family-direct-manipulation-swift/branch/develop/graph/badge.svg)](https://codecov.io/gh/material-motion/material-motion-family-direct-manipulation-swift)
 
+## Supported languages
+
+- Swift 3
+- Objective-C
+
+## Features
+
+This library consists of the following plans:
+
+- `Draggable`, `Pinchable`, and `Rotatable`
+- `DirectlyManipulable`
+- `ChangeAnchorPoint`
+
+The `Draggable`, `Pinchable`, and `Rotatable` plans allow a user to move, scale, and rotate a view.
+They each listen for deltas emitted by a gesture recognizer and add them to the target.
+
+If a view can be dragged then it can often be pinched and rotated too. To make this easy, we provide
+a `DirectlyManipulable` plan. It's equivalent to individually adding `Draggable`, `Pinchable`, and
+`Rotatable` to the same target.
+
+The collection of `Draggable`, `Pinchable`, `Rotatable`, and `DirectlyManipulable` represent traits
+that can describe behavior of a target view. When any of these traits are added to a view the view's
+`isUserInteractionEnabled` is enabled. If the plan's associated gesture recognizer is not yet
+associated with a view then the gesture recognizer will be added to the target view.
+
+`ChangeAnchorPoint` adjusts `view.layer.anchorPoint` while maintaining the same `view.frame`. In
+practice you will not use this plan directly because `Draggable`, `Pinchable`, and `Rotatable` each
+provide the `shouldAdjustAnchorPointOnGestureStart` property for automatically emitting a
+ChangeAnchorPoint instance.
+
 ## Installation
 
 ### Installation with CocoaPods
@@ -42,12 +72,58 @@ commands:
 
 ## Guides
 
-1. [Architecture](#architecture)
-2. [How to ...](#how-to-...)
+1. [How to make a view directly manipulable](#how-to-make-a-view-directly-manipulable)
+2. [How to make a view draggable](#how-to-make-a-view-draggable)
+3. [How to use an existing gesture recognizer to make a view draggable](#how-to-use-an-existing-gesture-recognizer-to-make-a-view-draggable)
+
+### How to make a view directly manipulable
+
+Code snippets:
+
+***In Objective-C:***
+
+```objc
+[runtime addPlan:[MDMDirectlyManipulable new] to:<#Object#>];
+```
+
+***In Swift:***
+
+```swift
+runtime.addPlan(DirectlyManipulable(), to: <#Object#>)
+```
+
+### How to make a view draggable
+
+Code snippets:
+
+***In Objective-C:***
+
+```objc
+[runtime addPlan:[MDMDraggable new] to:<#Object#>];
+```
+
+***In Swift:***
+
+```swift
+runtime.addPlan(Draggable(), to: <#Object#>)
+```
+
+### How to use an existing gesture recognizer to make a view draggable
+
+Code snippets:
+
+***In Objective-C:***
+
+```objc
+MDMDraggable *draggable = [[MDMDraggable alloc] initWithGestureRecognizer:panGestureRecognizer];
+[runtime addPlan:draggable to:<#Object#>];
+```
 
-### Architecture
+***In Swift:***
 
-### How to ...
+```swift
+runtime.addPlan(Draggable(withGestureRecognizer: panGestureRecognizer), to: <#Object#>)
+```
 
 ## Contributing