Use bundler to handle Ruby gems.

Gemfile

@@ -0,0 +1,3 @@
+source 'https://rubygems.org'
+gem 'jekyll', '~> 2.5.3'
+gem 'rouge', '~> 1.8.0'

Gemfile.lock

@@ -0,0 +1,72 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    blankslate (2.1.2.4)
+    celluloid (0.16.0)
+      timers (~> 4.0.0)
+    classifier-reborn (2.0.3)
+      fast-stemmer (~> 1.0)
+    coffee-script (2.4.1)
+      coffee-script-source
+      execjs
+    coffee-script-source (1.9.1.1)
+    colorator (0.1)
+    execjs (2.5.2)
+    fast-stemmer (1.0.2)
+    ffi (1.9.8-x64-mingw32)
+    hitimes (1.2.2)
+    jekyll (2.5.3)
+      classifier-reborn (~> 2.0)
+      colorator (~> 0.1)
+      jekyll-coffeescript (~> 1.0)
+      jekyll-gist (~> 1.0)
+      jekyll-paginate (~> 1.0)
+      jekyll-sass-converter (~> 1.0)
+      jekyll-watch (~> 1.1)
+      kramdown (~> 1.3)
+      liquid (~> 2.6.1)
+      mercenary (~> 0.3.3)
+      pygments.rb (~> 0.6.0)
+      redcarpet (~> 3.1)
+      safe_yaml (~> 1.0)
+      toml (~> 0.1.0)
+    jekyll-coffeescript (1.0.1)
+      coffee-script (~> 2.2)
+    jekyll-gist (1.2.1)
+    jekyll-paginate (1.1.0)
+    jekyll-sass-converter (1.3.0)
+      sass (~> 3.2)
+    jekyll-watch (1.2.1)
+      listen (~> 2.7)
+    kramdown (1.7.0)
+    liquid (2.6.2)
+    listen (2.10.0)
+      celluloid (~> 0.16.0)
+      rb-fsevent (>= 0.9.3)
+      rb-inotify (>= 0.9)
+    mercenary (0.3.5)
+    parslet (1.5.0)
+      blankslate (~> 2.0)
+    posix-spawn (0.3.11)
+    pygments.rb (0.6.3)
+      posix-spawn (~> 0.3.6)
+      yajl-ruby (~> 1.2.0)
+    rb-fsevent (0.9.4)
+    rb-inotify (0.9.5)
+      ffi (>= 0.5.0)
+    redcarpet (3.2.3)
+    rouge (1.8.0)
+    safe_yaml (1.0.4)
+    sass (3.4.13)
+    timers (4.0.1)
+      hitimes
+    toml (0.1.2)
+      parslet (~> 1.5.0)
+    yajl-ruby (1.2.1)
+
+PLATFORMS
+  x64-mingw32
+
+DEPENDENCIES
+  jekyll (~> 2.5.3)
+  rouge (~> 1.8.0)

Gruntfile.js

@@ -309,6 +309,7 @@ module.exports = function (grunt) {
 
     jekyll: {
       options: {
+        bundleExec: true,
         config: '_config.yml'
       },
       docs: {},

README.md

@@ -73,10 +73,10 @@ Bootstrap's documentation, included in this repo in the root directory, is built
 
 ### Running documentation locally
 
-1. If necessary, [install Jekyll](http://jekyllrb.com/docs/installation) (requires v2.5.x).
-  - **Windows users:** Read [this unofficial guide](http://jekyll-windows.juthilo.com/) to get Jekyll up and running without problems.
-2. Install the Ruby-based syntax highlighter, [Rouge](https://github.com/jneen/rouge), with `gem install rouge`.
-3. From the root `/bootstrap` directory, run `jekyll serve` in the command line.
+1. Install [bundler](http://bundler.io/) via `gem install bundle`.
+  - **Windows users:** Read [this unofficial guide](http://jekyll-windows.juthilo.com/) to get Ruby up and running without problems.
+2. Install the Ruby Gems: `bundle install`.
+3. From the root `/bootstrap` directory, run `bundle exec jekyll serve` in the command line.
 4. Open <http://localhost:9001> in your browser, and voilà.
 
 Learn more about using Jekyll by reading its [documentation](http://jekyllrb.com/docs/home/).

docs/_includes/getting-started/grunt.html

@@ -25,7 +25,7 @@
   <p>Runs <a href="http://jshint.com">JSHint</a> and runs the <a href="http://qunitjs.com">QUnit</a> tests headlessly in <a href="http://phantomjs.org">PhantomJS</a>.</p>
 
   <h3><code>grunt docs</code> (Build &amp; test the docs assets)</h3>
-  <p>Builds and tests CSS, JavaScript, and other assets which are used when running the documentation locally via <code>jekyll serve</code>.</p>
+  <p>Builds and tests CSS, JavaScript, and other assets which are used when running the documentation locally via <code>bundle exec jekyll serve</code>.</p>
 
   <h3><code>grunt</code> (Build absolutely everything and run tests)</h3>
   <p>Compiles and minifies CSS and JavaScript, builds the documentation website, runs the HTML5 validator against the docs, regenerates the Customizer assets, and more. Requires <a href="http://jekyllrb.com/docs/installation/">Jekyll</a>. Usually only necessary if you're hacking on Bootstrap itself.</p>

test-infra/S3Cachefile.json

@@ -7,6 +7,6 @@
     "rubygems": {
         "key": "../pseudo_Gemfile.lock",
         "cache": "$GEMDIR",
-        "generate": "gem install -N jekyll -v $JEKYLL_VERSION && gem install -N rouge -v $ROUGE_VERSION"
+        "generate": "bundle install"
     }
 }