docs: add initial files for mkdocs support

docs/_overrides/main.html

@@ -0,0 +1,49 @@
+<!--
+  Copyright (c) 2016-2022 Martin Donath <martin.donath@squidfunk.com>
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to
+  deal in the Software without restriction, including without limitation the
+  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+  sell copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+  IN THE SOFTWARE.
+-->
+
+{% extends "base.html" %}
+
+<!-- Custom front matter -->
+{% block extrahead %}
+
+  <!-- Extra style sheets (can't be set in mkdocs.yml due to content hash) -->
+  <link
+    rel="stylesheet"
+    href="{{ 'overrides/assets/stylesheets/main.css' | url }}"
+  />
+{% endblock %}
+
+<!-- Announcement bar -->
+{% block announce %}
+  <a href="https://twitter.com/dokku">
+    For updates follow <strong>@dokku</strong> on
+    <span class="twemoji twitter">
+      {% include ".icons/fontawesome/brands/twitter.svg" %}
+    </span>
+    <strong>Twitter</strong>
+  </a>
+{% endblock %}
+
+<!-- Theme-related JavaScript -->
+{% block scripts %}
+  {{ super() }}
+
+  <!-- Extra JavaScript (can't be set in mkdocs.yml due to content hash) -->
+  <script src="{{ 'overrides/assets/javascripts/bundle.js' | url }}"></script>
+{% endblock %}