Add new docs Versions page.

site/_data/docs-versions.yml

+- group: v1.x
+  baseurl: https://getbootstrap.com
+  description: Every minor and patch release from v1 is listed below.
+  versions:
+    - v: 1.0.0
+    - v: 1.1.0
+    - v: 1.1.1
+    - v: 1.2.0
+    - v: 1.3.0
+    - v: 1.4.0
+
+- group: v2.x
+  baseurl: https://getbootstrap.com
+  description: Every minor and patch release from v2 is listed below.
+  versions:
+    - v: 2.0.0
+    - v: 2.0.1
+    - v: 2.0.2
+    - v: 2.0.3
+    - v: 2.0.4
+    - v: 2.1.0
+    - v: 2.1.1
+    - v: 2.2.0
+    - v: 2.2.1
+    - v: 2.2.2
+    - v: 2.3.0
+    - v: 2.3.1
+    - v: 2.3.2
+
+- group: v3.x
+  baseurl: https://getbootstrap.com/docs
+  description: Single docs site for our previous major release. Last update was v3.3.7.
+  versions:
+    - v: 3.3
+
+- group: v4.x
+  baseurl: https://getbootstrap.com/docs
+  description: Current major release with two minor releases. Last update was v4.1.3.
+  versions:
+    - v: 4.0
+    - v: 4.1

site/_includes/docs-navbar.html

@@ -38,6 +38,8 @@
         <a class="dropdown-item" href="https://v4-alpha.getbootstrap.com/">v4 Alpha 6</a>
         <a class="dropdown-item" href="https://getbootstrap.com/docs/3.3/">v3.3.7</a>
         <a class="dropdown-item" href="https://getbootstrap.com/2.3.2/">v2.3.2</a>
+        <div class="dropdown-divider"></div>
+        <a class="dropdown-item" href="https://getbootstrap.com/docs/versions/">All versions</a>
       </div>
     </li>
 

site/_layouts/simple.html

@@ -2,11 +2,4 @@
 layout: default
 ---
 
-<div class="container my-5">
-  <main class="bd-content" role="main">
-    <h1 class="bd-title" id="content">{{ page.title | smartify }}</h1>
-    <p class="bd-lead">{{ page.description | smartify }}</p>
-    {% include ads.html %}
-    {{ content }}
-  </main>
-</div>
+{{ content }}

site/docs/versions.html

+---
+layout: simple
+title: Versions
+description: An appendix of hosted documentation for nearly every release of Bootstrap, from v1 through v4.
+---
+
+<header class="d-flex flex-column flex-md-row align-items-md-center p-5 bg-light">
+  <div class="pt-md-3 pb-md-4">
+    <h1 class="bd-title mt-0">{{ page.title | smartify }}</h1>
+    <p class="bd-lead">{{ page.description | smartify }}</p>
+  </div>
+  {% include ads.html %}
+</header>
+
+<main class="bd-content p-5">
+  <div class="row">
+  {% for release in site.data.docs-versions %}
+    <div class="col-md">
+      <h1>{{ release.group }}</h1>
+      <p>{{ release.description }}</p>
+      {% for version in release.versions %}
+        {% if forloop.first %}<div class="list-group">{% endif %}
+          {% if version.v == site.docs_version %}
+            <a class="list-group-item list-group-item-action py-2 text-primary d-flex justify-content-between align-items-center" href="{{ release.baseurl }}/{{ version.v }}/">
+              {{ version.v }}
+              <span class="badge badge-primary">Latest</span>
+            </a>
+          {% else %}
+            <a class="list-group-item list-group-item-action py-2 text-primary" href="{{ release.baseurl }}/{{ version.v }}/">
+              {{ version.v }}
+            </a>
+          {% endif %}
+        {% if forloop.last %}</div>{% endif %}
+      {% endfor %}
+    </div>
+  {% endfor %}
+  </div>
+</main>