update readme

Author: phated

README.md

@@ -1,4 +1,48 @@
-undertaker-common-tasks
-=======================
+<p align="center">
+  <a href="http://gulpjs.com">
+    <img height="257" width="114" src="https://raw.githubusercontent.com/gulpjs/artwork/master/gulp-2x.png">
+  </a>
+</p>
 
-Proof of concept for custom Undertaker registries that pre-define tasks
+# undertaker-common-tasks
+
+[![NPM version][npm-image]][npm-url] [![Downloads][downloads-image]][npm-url] [![Build Status][travis-image]][travis-url] [![Gitter chat][gitter-image]][gitter-url]
+
+Proof-of-concept custom registry that pre-defines tasks.
+
+## Example
+
+```js
+var gulp = require('gulp');
+var CommonTasks = require('undertaker-common-tasks');
+
+gulp.registry(new CommonTasks({ port: 1337, buildDir: './dist' }));
+
+// 'clean' & 'series' were defined by the registry
+gulp.task('default', gulp.series('clean', 'serve'));
+```
+
+## API
+
+### CommonTasksRegistry([options])
+
+Constructor for the registry. Pass an instance of this registry to `gulp.registry`.
+
+#### options
+
+* `port` - the port to start a static webserver on.
+* `buildDir` - the output directory (clean deletes this directory).
+
+## License
+
+MIT
+
+[downloads-image]: http://img.shields.io/npm/dm/undertaker-common-tasks.svg
+[npm-url]: https://npmjs.org/package/undertaker-common-tasks
+[npm-image]: http://img.shields.io/npm/v/undertaker-common-tasks.svg
+
+[travis-url]: https://travis-ci.org/gulpjs/undertaker-common-tasks
+[travis-image]: http://img.shields.io/travis/gulpjs/undertaker-common-tasks.svg
+
+[gitter-url]: https://gitter.im/gulpjs/gulp
+[gitter-image]: https://badges.gitter.im/gulpjs/gulp.png