Add docs and credits for #439 and #443

docs/api.md

@@ -431,6 +431,7 @@ Overlay (composite) a image containing an alpha channel over the processed (resi
 `options`, if present, is an Object with the following optional attributes:
 
 * `gravity` is a String or an attribute of the `sharp.gravity` Object e.g. `sharp.gravity.north` at which to place the overlay, defaulting to `center`/`centre`.
+* `tile` is a Boolean, defaulting to `false`. When set to `true` repeats the overlay image across the entire image with the given `gravity`.
 
 ```javascript
 sharp('input.png')

docs/changelog.md

@@ -10,6 +10,14 @@ Requires libvips v8.3.1
   [#429](https://github.com/lovell/sharp/issues/429)
   [@papandreou](https://github.com/papandreou)
 
+* Add alpha channel, if required, before extend operation.
+  [#439](https://github.com/lovell/sharp/pull/439)
+  [@frulo](https://github.com/frulo)
+
+* Allow overlay image to be repeated across entire image via tile option.
+  [#443](https://github.com/lovell/sharp/pull/443)
+  [@lemnisk8](https://github.com/lemnisk8)
+
 #### v0.15.0 - 21<sup>st</sup> May 2016
 
 * Use libvips' new Lanczos 3 kernel as default for image reduction.

docs/index.md

@@ -92,6 +92,8 @@ the help and code contributions of the following people:
 * [Kenton Gray](https://github.com/kentongray)
 * [Felix Bünemann](https://github.com/felixbuenemann)
 * [Samy Al Zahrani](https://github.com/salzhrani)
+* [Chintan Thakkar](https://github.com/lemnisk8)
+* [F. Orlando Galashan](https://github.com/frulo)
 
 Thank you!