introduce versioning scheme

Introduce scheme for maintaining multiple versions of the docs.  In
short, each version of the docs gets a top-level subdirectory, like
`v1.0`, with a copy of each page within.  See comments in
_plugins/version.rb for details.

Gemfile

@@ -7,5 +7,6 @@ source "https://rubygems.org"
 
 gem "html-proofer", "~> 3.7"
 gem "jekyll", "~> 3.4"
+gem "jekyll-redirect-from", "~> 0.12"
 gem "rake", "~> 12.0.0"
 gem "redcarpet", "~> 3.4"

Gemfile.lock

@@ -36,6 +36,8 @@ GEM
       pathutil (~> 0.9)
       rouge (~> 1.7)
       safe_yaml (~> 1.0)
+    jekyll-redirect-from (0.12.1)
+      jekyll (~> 3.3)
     jekyll-sass-converter (1.5.0)
       sass (~> 3.4)
     jekyll-watch (1.5.0)
@@ -75,6 +77,7 @@ PLATFORMS
 DEPENDENCIES
   html-proofer (~> 3.7)
   jekyll (~> 3.4)
+  jekyll-redirect-from (~> 0.12)
   rake (~> 12.0.0)
   redcarpet (~> 3.4)
 

Rakefile

@@ -1,8 +1,11 @@
 require 'html-proofer'
+require 'yaml'
 
 task :htmlproofer do
+  baseurl = ENV['JEKYLL_BASEURL'] || YAML.load_file('_config.yml')['baseurl']
   HTMLProofer.check_directory("./_site", {
     :allow_hash_href => true,
+    :url_swap => { /^#{Regexp.quote(baseurl)}/ => '' },
     :typhoeus => {
       :ssl_verifypeer => false,
       :ssl_verifyhost => 0}

_config.yml

@@ -14,6 +14,21 @@ redcarpet:
   - tables
   - with_toc_data
 
+versions:
+  stable: v1.0
+  dev: v1.1
+
+release_info:
+  v1.0:
+    version: v1.0.2
+    build_time: 2017/06/15 12:56:53 (go1.8.3)
+    start_time: 2017-06-15 10:29:13.675508543 -0400 EDT
+  v1.1:
+    name: v1.1-alpha
+    version: v1.1-alpha.20170622
+    build_time: 2017/06/22 11:43:06
+    start_time: 2017-06-22 11:43:07.546315789 -0400 EDT
+
 exclude: ["ci", "set-application-name.md", "vendor"]
 
 defaults:

_includes/back-to-top.html

@@ -1,5 +1,5 @@
 <!-- back to top button -->
-<div class="scroll-to-top"><img src="images/back_to_top.png" alt="Scroll back to top" onmouseover="this.src='images/back_to_top_hover.png';" onmouseout="this.src='images/back_to_top.png';"/></div>
+<div class="scroll-to-top"><img src="{{ 'images/back_to_top.png' | relative_url }}" alt="Scroll back to top" onmouseover="this.src='images/back_to_top_hover.png';" onmouseout="this.src='images/back_to_top.png';"/></div>
 
 <script>
 (function($){

_includes/head.html

@@ -4,29 +4,29 @@
 <meta name="description" content="{% if page.summary %}{{ page.summary | strip_html | strip_newlines | truncate: 160 }}{% endif %}">
 <meta name="keywords" content="{{page.tags}}{% if page.tags %}, {% endif %} {{page.keywords}}">
 <title>{{ page.title }} | {{ site.site_title }}</title>
-<link rel="canonical" href="{{ site.url }}{{ site.baseurl }}{% if page.url != '/index.html' %}{{ page.url }}{% endif %}" data-proofer-ignore>
-<link rel="shortcut icon" href="images/favicon.png" type="image/png">
+<link rel="canonical" href="{{ page.canonical | absolute_url }}">
+<link rel="shortcut icon" href="{{ 'images/favicon.png' | relative_url }}" type="image/png">
 
-<link rel="stylesheet" type="text/css" href="css/font-awesome.min.css">
-<link rel="stylesheet" type="text/css" href="css/lavish-bootstrap.css">
-<link rel="stylesheet" type="text/css" href="css/customstyles.css">
-<link rel="stylesheet" type="text/css" href="css/theme-blue.css">
-{% if page.asciicast == true %}<link rel="stylesheet" type="text/css" href="css/asciinema-player.css">{% endif %}
+<link rel="stylesheet" type="text/css" href="{{ 'css/font-awesome.min.css' | relative_url }}">
+<link rel="stylesheet" type="text/css" href="{{ 'css/lavish-bootstrap.css' | relative_url }}">
+<link rel="stylesheet" type="text/css" href="{{ 'css/customstyles.css' | relative_url }}">
+<link rel="stylesheet" type="text/css" href="{{ 'css/theme-blue.css' | relative_url }}">
+{% if page.asciicast == true %}<link rel="stylesheet" type="text/css" href="{{ 'css/asciinema-player.css' | relative_url }}">{% endif %}
 
 <script>
 var pageConfig = {
     tocNotNested: {% if page.toc_not_nested %}true{% else %}false{% endif %}
 };
 </script>
 
-<script src="js/jquery.min.js"></script>
-<script src="js/jquery.cookie.min.js"></script>
-<script src="js/jquery.navgoco.min.js"></script>
-<script src="js/bootstrap.min.js"></script>
-<script src="js/toc.js"></script>
-<script src="js/clipboard.min.js"></script>
-<script src="js/customscripts.js"></script>
-<script src="js/anchor.js"></script>
+<script src="{{ 'js/jquery.min.js' | relative_url }}"></script>
+<script src="{{ 'js/jquery.cookie.min.js' | relative_url }}"></script>
+<script src="{{ 'js/jquery.navgoco.min.js' | relative_url }}"></script>
+<script src="{{ 'js/bootstrap.min.js' | relative_url }}"></script>
+<script src="{{ 'js/toc.js' | relative_url }}"></script>
+<script src="{{ 'js/clipboard.min.js' | relative_url }}"></script>
+<script src="{{ 'js/customscripts.js' | relative_url }}"></script>
+<script src="{{ 'js/anchor.js' | relative_url }}"></script>
 <script src="//js.hsforms.net/forms/v2.js"></script>
 {% if page.optimizely == true %}<script src="https://cdn.optimizely.com/js/7825500667.js"></script>{% endif %}
-{% if page.asciicast == true %}<script src="js/asciinema-player.js"></script>{% endif %}
+{% if page.asciicast == true %}<script src="{{ 'js/asciinema-player.js' | relative_url }}"></script>{% endif %}

_includes/newsletter-popout.html

@@ -13,7 +13,7 @@
 			});
 		</script>
 	</div>
-	<div class="newsletter-close"><img src="images/close_icon.png" style="max-width: 36px;" data-proofer-ignore/></div>
+	<div class="newsletter-close"><img src="{{ 'images/close_icon.png' | relative_url }}" style="max-width: 36px;" data-proofer-ignore/></div>
 </div>
 
 <div id="newsletter-footer-popout">
@@ -37,7 +37,7 @@
 			</div>
 		</div>
 	</div>
-	<div class="newsletter-close"><img src="images/close_icon.png" style="max-width: 25px;" data-proofer-ignore/></div>
+	<div class="newsletter-close"><img src="{{ 'images/close_icon.png' | relative_url }}" style="max-width: 25px;" data-proofer-ignore/></div>
 </div>
 
 <script>