Add Bundler Installation Instructions (jekyll#6828)

Merge pull request 6828

docs/_data/tutorials.yml

@@ -6,6 +6,7 @@
   - orderofinterpretation
   - custom-404-page
   - convert-site-to-jekyll
+  - using-jekyll-with-bundler
 
 #- title: Another section
 #  tutorials:

docs/_tutorials/using-jekyll-with-bundler.md

@@ -0,0 +1,106 @@
+---
+layout: tutorials
+permalink: /tutorials/using-jekyll-with-bundler/
+title: Using Jekyll with Bundler
+---
+
+> Bundler provides a consistent environment for Ruby projects by tracking and
+> installing the exact gems and versions that are needed.
+
+[Bundler](https://bundler.io) can be a great tool to use with Jekyll. Because it
+tracks dependencies on a per-project basis, it is particularly useful if you
+need to run different versions of Jekyll in different projects, or if you don't
+want to install Jekyll at the system or user level. This tutorial will show you
+how to create a new Jekyll project using Bundler and without installing Jekyll
+outside the project.
+
+## Before You Begin
+
+To complete this tutorial, you'll need to have
+[Ruby](https://www.ruby-lang.org/en/) and [Bundler](https://bundler.io/)
+installed. You can find the installation instructions on their websites.
+
+## Initialize Bundler
+
+The first thing to do is create a new directory for your project and run
+`bundle init`. This creates a new Bundler project (by creating an empty
+Gemfile).
+
+```sh
+mkdir my-jekyll-website
+cd my-jekyll-website
+bundle init
+```
+
+## Configure Bundler
+
+This step is optional, but encouraged. We're going to configure Bundler to install
+gems in the `./vendor/bundle/` project subdirectory. This allows us to install
+our dependencies in an isolated environment, ensuring they don't conflict with
+other gems on your system. If you skip this step, Bundler will install your
+dependencies globally on your system.
+
+```sh
+bundle install --path vendor/bundle
+```
+
+<div class="note info">
+  <h5>Bundler Config is Persistent</h5>
+  <p>
+    This step is only required once per project. Bundler saves your config in
+    <code>./.bundle/config</code>, so future gems will be installed to the same
+    location.
+  </p>
+</div>
+
+## Add Jekyll
+
+Now, we're going to use Bundler to add Jekyll as a dependency of our new
+project. This command will add the Jekyll gem to our Gemfile and install it to
+the `./vendor/bundle/` folder.
+
+```sh
+bundle add jekyll
+```
+
+## Create A Jekyll Scaffold
+
+Now that Jekyll is installed, we can use it to create the scaffolding for our
+site. We need the `--force` parameter because our folder isn't empty - it
+already has some Bundler files in it. We run the `bundle install` separately
+because Jekyll gets confused if the Gemfile already exists.
+
+```sh
+bundle exec jekyll new --force --skip-bundle .
+bundle install
+```
+
+## Serve the Site
+
+Your new website is ready! You can serve the website with
+`bundle exec jekyll serve` and visit it at
+[http://127.0.0.1:4000](http://127.0.0.1:4000). From here, you're ready to
+continue developing the site on your own. All of the normal Jekyll commands are
+available to you, but you should prefix them with `bundle exec` so that Bundler
+runs the version of Jekyll that is installed in your project folder.
+
+## Commit to Source Control
+
+If you're storing your new site in version control, you'll want to ignore the
+`./vendor/` and `./.bundle/` folders since they contain user- or
+platform-specific information. New users will be able to install the correct
+dependencies based on `Gemfile` and `Gemfile.lock`, which should both be checked
+in. You can use this `.gitigonre` to get started, if you want.
+
+**.gitignore**
+
+```
+# Ignore folders generated by Bundler
+vendor
+.bundle
+
+# Ignore folders generated by Jekyll
+.sass-cache
+_site
+```
+