docs: begin writeup of guard

While writing this I realized that this really should be part of part_3_workflows.rst, so it'll eventually make it into there. But it's recorded in its unpolished form for now.

docs/guides/getting-started/part_3_workflows.rst

@@ -7,6 +7,7 @@ The Squib Way pt 3: Workflows
 
 * Setting up rake tasks
 * Splitting out decks into different files
+* Build groups: testing, marketing, rulebook figures
 * Build groups: color vs. black-and-white
 * Switch from built-in layouts to your own layout
 * Launch what you need with Launchy

docs/guides/guard.rst

@@ -1,6 +1,84 @@
-Squib + Guard
-=============
+Autobuild with Guard
+====================
 
 .. warning::
 
-  To be written.
+  Under construction - going to fold this into the Workflow guide. For now, you can see my samples. This is mostly just a brain dump.
+
+Throughout your prototyping process, you'll be making small adjustments and then examining the graphical output. Re-running your code can get tedious, because you're cognitively switching from one context to another, e.g. editing x-y coordinates to running your code.
+
+Ruby has a great tool for this: `Guard <https://github.com/guard/guard>`_. With Guard, you specify one configuration file (i.e. a ``Guardfile``), and then Guard will *watch* a set of files, then execute a *task*. There are many ways of executing a task, but the cleanest way is via a ``rake`` in a ``Rakefile``.
+
+Project layout
+--------------
+
+Here's our project layout:
+
+.. code-block:: text
+
+  .
+  ├── config.yml
+  ├── Gemfile
+  ├── Guardfile
+  ├── img
+  │   └── robot-golem.svg
+  ├── layouts
+  │   ├── characters.yml
+  │   └── skills.yml
+  ├── Rakefile
+  └── src
+    ├── characters.rb
+    └── skills.rb
+
+Using Guard + Rake
+------------------
+
+Guard is a gem, just like Squib. When using Guard, I recommend also using Bundler. So your Gemfile will look like this.
+
+.. literalinclude:: ../../samples/rake-guard/Gemfile
+  :language: ruby
+  :linenos:
+
+And then your Rakefile might look something like this
+
+.. literalinclude:: ../../samples/rake-guard/Rakefile
+  :language: ruby
+  :linenos:
+
+To get our images directory set, and to turn on proress bars (which I recommend when working under Guard), you'll need a ``config.yml`` file that looks like this.
+
+.. literalinclude:: ../../samples/rake-guard/config.yml
+  :language: yaml
+  :linenos:
+
+Note that we are using ``load`` instead of ``require`` to run our code. In Ruby, ``require`` will only run our code once, because it's about loading a library. The ``load`` will run Ruby code no matter whether or not it's been loaded before. This doesn't usually matter, unless you're running under Guard.
+
+And then our Guardfile
+
+.. literalinclude:: ../../samples/rake-guard/Guardfile
+  :language: ruby
+  :linenos:
+
+
+So, let's say we're working on our Character deck. To run all this we can kick off our Guard with:
+
+.. code-block:: text
+
+  $ bundle exec guard -g characters
+  14:45:20 - INFO - Run 'gem install win32console' to use color on Windows
+  14:45:21 - INFO - Starting guard-rake characters
+  14:45:21 - INFO - running characters
+  Loading SVG(s) <===========================================> 100% Time: 00:00:00
+  Saving PNGs to _output/character__* <======================> 100% Time: 00:00:00
+  ]2;[running rake task: characters] watched files: []
+  [1] Characters guard(main)> ow watching at 'C:/Users/andy/code/squib/samples/rake-guard'
+
+Guard will do an initial build, then wait for file changes to be made. From here, once we edit and save anything related to characters - any Excel file, our ``characters.rb`` file, any YML file, etc, we'll rebuild our images.
+
+Guard can do much, much more. It opens up a debugging console based on `pry <http://pryrepl.org/>`_, which means if your code is broken you can test things out right there.
+
+Guard also supports all kinds of notifications too. By default it tends to beep, but you can also have visual bells and other notifications.
+
+To quit guard, type ``quit`` on their console. Or, you can do ``Ctrl+C`` to quit.
+
+Enjoy!