Write up some instructions

README.md

@@ -1,8 +1,33 @@
-# [WIP] ember-cli-autoprefixer
-This addon runs your compiled styles through `autoprefixer`.
+# Autoprefixer for Ember CLI
+This addon runs the styles of your EmberCLI-project through
+`autoprefixer`.
 
-## NOT USABLE
-Waiting for this pull request to land: https://github.com/stefanpenner/ember-cli/pull/1214
+*NB*: This addon requires Ember CLI version `0.0.39` or newer.
+
+## Install
+To install, run
+
+```
+npm install ember-cli-autoprefixer --save-dev
+```
+
+## Options
+You can configure what browsers to target by specifying them in your
+`Brocfile.js`. An example:
+
+```js
+var app = new EmberApp({
+  autoprefixer: {
+    browsers: ['last 2 ios version']
+  }
+});
+```
+
+This would prefix styles as required by the two latest version of ios.
+
+The default value for `browsers` are `['> 1%', 'last 2 versions', 'Firefox ESR', 'Opera 12.1']`.
+
+You can read more about this setting [over on the autoprefixer page](https://github.com/ai/autoprefixer#browsers).
 
 ## References
 - [Autoprefixer](https://github.com/ai/autoprefixer)