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Readme.md

@@ -9,7 +9,35 @@
 
 ## API
 
-
+### Tween(obj)
+
+  Initialize a new `Tween` with `obj`.
+
+### Tween#reset()
+
+  Reset the tween.
+
+### Tween#to(obj:Object)
+
+  Tween to `obj` and reset internal state.
+
+     tween.to({ x: 50, y: 100 })
+
+### Tween#duration(ms:Number)
+
+  Set duration to `ms` [500].
+
+### Tween#ease(fn:String|Function)
+
+  Set easing function to `fn`.
+
+     tween.ease('in-out-sine')
+
+### Tween#update(fn:Function)
+
+  Set update function to `fn` or 
+  when no argument is given this performs
+  a "step".
 
 ## License