add bundler installation and comprehensive setup instructions

setup.md

@@ -174,44 +174,206 @@ before pushing them to GitHub.
 
 In order to preview changes locally, you must install the software described below.
 
-1.  **[Ruby](https://www.ruby-lang.org/en/downloads/)**.
-
-    **Linux/macOS**: Ruby is usually included with Linux and macOS ---
-    this is usually sufficient to preview your changes locally.
-
-    If you aren't able to preview reliably with your default Ruby installation,
-    you can use the same version of Ruby as GitHub. Currently,
-    GitHub uses Ruby 2.5.3. In order to install Ruby 2.5.3 on Linux and macOS, we recommend using
-    [rbenv](https://github.com/rbenv/rbenv):
-
+### Windows
+
+#### Option 1 - Using the Windows Subsystem for Linux (WSL)
+
+If your version of Windows supports it, using the WSL will make the installation of the tools needed easier. Instructions to install Linux distributions from Windows 10/Windows Server are available from the [Microsoft website](https://docs.microsoft.com/en-us/windows/wsl/about).
+
+Once you have installed a Linux distribution, you can follow the installation instructions for [Linux](#linux-ubuntu) listed below. If you install a distribution other than Ubuntu, you'll need to adjust the commands that install the packages. 
+
+#### Option 2 - Using Windows
+
+With the instructions below, you'll be able to preview websites for non-R based lessons. You'll be able to do so from the Git Bash terminal or from the "Command Prompt with Ruby" that comes with the Ruby installation. You won't be able to use the `make` commands as Make isn't available from the Git Bash terminal (see the optional section below for more info).
+
+1. **Ruby**, go to <https://rubyinstaller.org/> choose Ruby+DevKit for your
+   system (typically x64), and the most recent version available. During the
+   installation process, choose to install the MSYS2 toolchain. On the last step
+   of the installation screen, make sure that "Run 'ridk install'" is checked.
+   This will bring a terminal window with 3 options, press "Enter" (for the
+   default installation). After this step completes, you'll be prompted again,
+   and press "Enter" again (for the default option). Once the installation is
+   complete, restart your system.
+
+2. Navigate to the folder that contains the lesson, and you can now use `bundle
+   exec jekyll serve` from your Git Bash terminal to preview the lessons.
+
+##### Optional (but recommended)
+
+With these instructions, you'll be able to use the `make` commands and render
+all lessons including those that use R. However, you won't be able to do so from the Git Bash terminal, but from the other terminals (Windows Powershell, cmd.exe, or the Command Prompt with Ruby).
+
+1. In the File Explorer, right-click on "This PC" icon, and click on
+   "Properties". Click on "Advanced System Settings", and click on the button
+   "Environment Variables". Click on the variable "Path", and then the "Edit"
+   button. Click on the "New" button and add `C:\Ruby26-x64\msys64\usr\bin` (use
+   the File Explorer to make sure this is the correct path for your Ruby and
+   MSYS2 installation). If you're working on R-based lessons and R isn't already
+   listed there, you need to add it by adding `C:\Program Files\R\R-3.x.x\bin`
+   (using the correct path and R version number for your installation).
+
+2. Open the "Command Prompt with Ruby" (if it was open before you edited the
+   Path, close it and re-open it).
+
+3. Go to the section [For Everyone](#for-everyone)
+
+### macOS
+
+1. First make sure you have Homebrew installed by doing
+
+To install brew, open the [Homebrew website](https://brew.sh/) and copy/paste the first command
+on that page into your Terminal. It will look something like: 
+
+  ~~~
+  /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
+  ~~~
+  {: .language-bash}
+
+ If you're not sure whether you have brew installed, type
+
+  ~~~
+  brew help
+  ~~~
+  {: .language-bash}
+
+  If you have brew installed, you should see something like:
+
+  ~~~
+  Example usage:
+  brew search [TEXT|/REGEX/]
+  brew info [FORMULA...]
+  brew install FORMULA...
+  brew update
+  brew upgrade [FORMULA...]
+  brew uninstall FORMULA...
+  brew list [FORMULA...]
+
+Troubleshooting:
+  brew config
+  brew doctor
+  brew install --verbose --debug FORMULA
+
+Contributing:
+  brew create [URL [--no-fetch]]
+  brew edit [FORMULA...]
+
+Further help:
+  brew commands
+  brew help [COMMAND]
+  man brew
+  https://docs.brew.sh
+  ~~~
+  {: .output}
+
+
+2. **Ruby** -- `brew install ruby`
+
+3. **bundler** -- `gem install bundler --user-install`
+
+4. Go to the section [For Everyone](#for-everyone)
+
+### Linux (Ubuntu)
+
+1.  **[Ruby](https://www.ruby-lang.org/en/downloads/)** and other dependencies.
+
+    You will need to have the following packages installed (some might already
+    be on your system):
+
     ~~~
-    rbenv install 2.5.3
+    sudo apt-get install ruby ruby-dev build-essential libxml2-dev
     ~~~
     {: .language-bash}
-
-    And then instructing `rbenv` to use it in your lesson development process by executing the
-    following command from your lesson directory:
+
+2. **[bundler](https://bundler.io/)**
 
     ~~~
-    rbenv local 2.5.3
+    gem install bundler --user-install
     ~~~
     {: .language-bash}
+
+    `gem` is the package management framework for Ruby. It was installed as part
+    of Ruby in the step above. `bundler` is also a package manager but at the
+    scale of a project instead of being system-wide. It makes it easier to
+    manage dependencies.
 
-    To install `rbenv`, please use [rbenv-installer](https://github.com/rbenv/rbenv-installer).
 
-    **Windows**: Please use [RubyInstaller][ruby-installer] to install Ruby on Windows.
+### For Everyone
 
-    Upon installing Ruby, check its version by executing
+1. **The GitHub Pages Ruby Gem**
 
+    Make sure there is a `Gemfile` at the root of your lesson repository. This
+    file should only contain:
+
+    ~~~
+    source 'https://rubygems.org'
+    gem 'github-pages', group: :jekyll_plugins
     ~~~
-    ruby --version
+
+    If you don't have it, create it and the two lines above to it.
+
+    At the root of your repository type
+
+    ~~~
+    bundle update
+    ~~~
+    {: .language-bash}
+
+    If you haven't used `bundler` yet for your project, this command will
+    install all the needed dependencies. Otherwise, it will update them to match
+    the current versions used by GitHub Pages.
+
+4. **Generate the lesson**
+
+    At this stage, you should be able to do:
+
+    ~~~
+    make serve
+    ~~~
+    {: .language-bash}
+
+    and see your generated lesson.
+
+### For R-based lessons
+
+You will need a recent version of R (>= 3.5.0). Installation instructions are available from the [CRAN website](https://cran.r-project.org). 
+
+We use the [knitr][cran-knitr],
+and[remotes](https://cran.r-project.org/package=remotes)to format lessons
+written in R Markdown and figure out needed packages to execute the code in the
+lesson. You will need to install the `remotes` package to build R lessons (and
+this example lesson). The best way to install these packages is to open an R
+terminal and type:
+
+~~~
+install.packages('remotes', repos = 'https://cran.rstudio.com')
+~~~
+{: .language-r}
+
+### Troubleshooting
+
+1. Check your version of Ruby:
+
+   ~~~
+   ruby -v
+   ~~~
+   {: .language-bash}
+
+   You need Ruby 2.1.0 or later (currently GitHub pages uses Ruby 2.5.3). If you
+   have an older version of Ruby, if possible upgrade your operating system to a
+   more recent version. If it's not possible, consider using [rbenv](https://github.com/rbenv/rbenv).
+
+    ~~~
+    rbenv install 2.5.3
     ~~~
     {: .language-bash}
 
-    Windows users should select the start menu option `Start command prompt with Ruby`
-    to execute the above command.
+    And then instructing `rbenv` to use it in your lesson development process by
+    executing the following command from your lesson directory:
 
-    For more information, see [the Ruby installation guidelines][ruby-install-guide].
+    ~~~
+    rbenv local 2.5.3
+    ~~~
+    {: .language-bash}
 
 2.  **[RubyGems][rubygems]**
     is a tool which manages Ruby packages. It should have been installed along with Ruby and you can
@@ -222,25 +384,9 @@ In order to preview changes locally, you must install the software described bel
     ~~~
     {: .language-bash}
 
-3.  **[Jekyll][jekyll]**.
-    You can install this by running `gem install jekyll`.
-    On macOS, a user does not have a permission to write to `/Library/Ruby/Gems/`.
-    Run `gem install jekyll --user-install` instead.
-
-4.  **R Packages**.
-    We use [knitr][cran-knitr], [stringr][cran-stringr], and [checkpoint][cran-checkpoint]
-    to format lessons written in R Markdown,
-    so you will need to install these to build R lessons
-    (and this example lesson). The best way to install these packages is to open an R terminal and type:
-
-    ~~~
-    install.packages(c('knitr', 'stringr', 'checkpoint', 'ggplot2'),
-                     repos = 'https://cran.rstudio.com', dependencies = TRUE)
-    ~~~
-    {: .language-r}
-
-If you want to run `bin/lesson_check.py` (which is invoked by `make lesson-check`)
+3. If you want to run `bin/lesson_check.py` (which is invoked by `make lesson-check`)
 you will need Jekyll (so that you have its Markdown parser, which is called Kramdown)
 and the [PyYAML][pyyaml] module for Python 3.
 
+
 {% include links.md %}