Use Gulp instead of Grunt

Ref: http://gulpjs.com/

.gitignore

@@ -1,3 +1,3 @@
-.tmp
 dist
 node_modules
+src/css/main.css

README.md

@@ -8,37 +8,34 @@ The HTML5 Boilerplate website is a simple static site.
 * The development code is in the
   [`src`](https://github.com/h5bp/html5boilerplate.com/tree/master/src)
   directory.
-* The build process relies on [Grunt](http://gruntjs.com) (a
+* The build process relies on [`Gulp`](http://gulpjs.com/) (a
   [Node.js](http://nodejs.org) task runner).
-* The Grunt configurations can be found in the
-  [`Gruntfile.js`](https://github.com/h5bp/html5boilerplate.com/blob/master/Gruntfile.js)
+* The `Gulp` configurations can be found in the
+  [`gulpfile.js`](https://github.com/h5bp/html5boilerplate.com/blob/master/gulpfile.js)
   file.
 
 ## Setup
 
 1. Install [Node.js and npm](http://nodejs.org/download/).
-2. [Install Grunt's command line interface (CLI)
-   globally](http://gruntjs.com/getting-started#installing-the-cli):
-   `npm install -g grunt-cli`.
-3. Run `npm install`.
+2. Run `npm install`.
 
 ## Development
 
 You should be able to work almost entirely in the
 [`src`](https://github.com/h5bp/html5boilerplate.com/tree/master/src) directory.
 
-While developing run `grunt dev` as this will open the website in your default
-browser and automatically update it whenever changes are made to the page or any
-of the files contained in the page.
+While developing run `npm run serve` as this will open the website in your
+default browser and automatically update it whenever changes are made to the
+page or any of the files contained in the page.
 
 ## Build
 
-When you have finished your changes, make sure that the distribution package is
-correct by running `grunt test` and then checking the output.
+When you have finished your changes, make sure that the distribution package
+is correct by running `npm run test` and then checking the output.
 
 ## Deploy
 
 This step is done automatically: the server will
 [periodically pull](https://github.com/h5bp/html5boilerplate.com/wiki) from
-the `server-content` branch, branch that will be updated by Travis CI every
-time a commit is pushed to the `master` branch and the tests pass.
+the `gh-pages` branch, branch that will be updated by Travis CI every time a
+commit is pushed to the `master` branch and the tests pass.