Merge branch 'v4-dev' of https://github.com/twbs/bootstrap into patch-1

1 files changed, 16 insertions, 10 deletions

diff --git a/docs/getting-started/build-tools.md b/docs/getting-started/build-tools.md
index adda6cbb1..0dabd30f9 100644
--- a/docs/getting-started/build-tools.md
+++ b/docs/getting-started/build-tools.md
@@ -13,7 +13,8 @@ To use our Gruntfile and run our documentation locally, you'll need a copy of Bo
 1. [Download and install Node](https://nodejs.org/download), which we use to manage our dependencies.
 2. Install the Grunt command line tools, `grunt-cli`, with `npm install -g grunt-cli`.
 3. Navigate to the root `/bootstrap` directory and run `npm install` to install our local dependencies listed in [package.json](https://github.com/twbs/bootstrap/blob/master/package.json).
-4. [Install Ruby][install-ruby], install [Bundler][gembundler] with `gem install bundler`, and finally run `bundle`. This will install all Ruby dependencies, such as Jekyll and Sass linter.
+4. [Install Ruby][install-ruby], install [Bundler][gembundler] with `gem install bundler`, and finally run `bundle install`. This will install all Ruby dependencies, such as Jekyll and plugins.
+  - **Windows users:** Read [this unofficial guide](http://jekyll-windows.juthilo.com/) to get Jekyll up and running without problems.
 
 When completed, you'll be able to run the various Grunt commands provided from the command line.
 
@@ -26,8 +27,8 @@ Our Gruntfile includes the following commands and tasks:
 
 | Task | Description |
 | --- | --- |
-| `grunt` | Run `grunt` to run tests locally and compile the CSS and JavaScript into `/dist`. **Uses [Sass](http://sass-lang.com/) and [UglifyJS](http://lisperator.net/uglifyjs/).** |
-| `grunt dist` | `grunt dist` creates the `/dist` directory with compiled files. **Uses [Sass](http://sass-lang.com/) and [UglifyJS](http://lisperator.net/uglifyjs/).** |
+| `grunt` | Run `grunt` to run tests locally and compile the CSS and JavaScript into `/dist`. **Uses [Sass](http://sass-lang.com/), [Autoprefixer][autoprefixer], and [UglifyJS](http://lisperator.net/uglifyjs/).** |
+| `grunt dist` | `grunt dist` creates the `/dist` directory with compiled files. **Uses [Sass](http://sass-lang.com/), [Autoprefixer][autoprefixer], and [UglifyJS](http://lisperator.net/uglifyjs/).** |
 | `grunt test` | Runs [scss-lint](https://github.com/brigade/scss-lint), [ESLint](http://eslint.org/) and [QUnit](http://qunitjs.com/) tests headlessly in [PhantomJS](http://phantomjs.org/) (used for CI). |
 | `grunt docs` | Builds and tests CSS, JavaScript, and other assets which are used when running the documentation locally via `jekyll serve`. |
 | `grunt watch` | This is a convenience method for watching just Sass files and automatically building them whenever you save. |
@@ -41,18 +42,17 @@ Bootstrap will be compiled with [libsass][libsass] by default, but you can opt i
 
 For example, run `TWBS_SASS=sass grunt` to test and build Bootstrap with Ruby Sass.
 
-[ruby-sass]: https://github.com/sass/sass
-[grunt-contrib-sass]: https://github.com/gruntjs/grunt-contrib-sass
-[libsass]: https://github.com/sass/libsass
-[grunt-sass]: https://github.com/sindresorhus/grunt-sass
+## Autoprefixer
+
+Bootstrap uses [Autoprefixer][autoprefixer] (included in our Gruntfile and build process) to automatically add vendor prefixes to some CSS properties at build time. Doing so saves us time and code by allowing us to write key parts of our CSS a single time while eliminating the need for vendor mixins like those found in v3.
+
 
 ## Local documentation
 
 Running our documentation locally requires the use of Jekyll, a decently flexible static site generator that provides us basic includes, Markdown-based files, templates, and more. Here's how to get it started:
 
-1. Run through the [tooling setup](#tooling-setup) above to install Jekyll (the site builder) and Rouge (our syntax highlighter).
-  - **Windows users:** Read [this unofficial guide](http://jekyll-windows.juthilo.com/) to get Jekyll up and running without problems.
-2. From the root `/bootstrap` directory, run `jekyll serve` in the command line.
+1. Run through the [tooling setup](#tooling-setup) above to install Jekyll (the site builder) and other Ruby dependencies with `bundle install`.
+2. From the root `/bootstrap` directory, run `bundle exec jekyll serve` in the command line.
 3. Open <http://localhost:9001> in your browser, and voilà.
 
 Learn more about using Jekyll by reading its [documentation](http://jekyllrb.com/docs/home/).
@@ -60,3 +60,9 @@ Learn more about using Jekyll by reading its [documentation](http://jekyllrb.com
 ## Troubleshooting
 
 Should you encounter problems with installing dependencies or running Grunt commands, uninstall all previous dependency versions (global and local). Then, rerun `npm install`.
+
+[ruby-sass]: https://github.com/sass/sass
+[grunt-contrib-sass]: https://github.com/gruntjs/grunt-contrib-sass
+[libsass]: https://github.com/sass/libsass
+[grunt-sass]: https://github.com/sindresorhus/grunt-sass
+[autoprefixer]: https://github.com/postcss/autoprefixer