Update CONTRIBUTING.md

Author: MoOx

CONTRIBUTING.md

@@ -1,14 +1,14 @@
 # Contributing
 
-_cssnext uses a lot of [postcss](https://github.com/postcss) plugins,
+_postcss-cssnext uses a lot of [postcss](https://github.com/postcss) plugins,
 so you might need to take a look at them if you find an issue or want to create
 or enhance a feature._
 
 Otherwise, fork, work on a branch, install dev-dependencies,
 respect coding style & run tests before submitting a bug fix or a feature.
 
 ```console
-$ git clone https://github.com/YOU/cssnext.git
+$ git clone https://github.com/YOU/postcss-cssnext.git
 $ npm install
 $ npm test
 $ git checkout -b fix.bug423
@@ -31,22 +31,14 @@ module directly in console._
 1. Add test files (input + expected output) in [`src/__tests__/fixtures/features`](src/__tests__/features)
 - If the feature can affect some others, update [`src/__tests__/fixtures/cases/example.css`](src/__tests__/cases/example.css) to test integration with other features
 
-- Choose a pretty simple and clear name (that match the specs)
-- Add the feature in the [README features list](#features) (title, link to spec, link of the plugin, short desc)
-- Add the feature in the [README node.js options list](#features-default-all-features) (camelCaseName)
-- Add the dependency in the [`package.json`](package.json)
-- Add the feature in the source (in [`index.js`](index.js)), in the appropriate place (order matter)
+- Choose a pretty simple and clear name (that match the specs), if you are not sure, ask using an issue.
+- Add the feature in :
+  - `docs/content/index.md` (http://cssnext.io/)
+  - `docs/content/features.md` (http://cssnext.io/features/) with an example + link to specs like others features
+- Add the dependency in the [`package.json`](package.json) (use `npm install --save postcss-...`)
+- Add the feature in the source (in [`src/features.js`](src/features.js)), in the appropriate place (order matter)
 For now, use a empty function instead of the right module
 - Run test, & check tests are broken (otherwise feature is useless)
-Now, call the right plugin
+Now, call the right plugin in the function you just created
 - Run test and be happy
-- Add feature in [the docs](docs/content)
 - Add feature on [the playground](docs/content/playground.html) example
-
-
-### Edit messages styles
-
-- default styles are in src/option.messages.browser.styles.js
-- test render by running: `babel-node src/__tests__/messages`.
-Styles will be compiled, rendered in a web page & the webpage will be opened for
-you.