diff --git a/.gitignore b/.gitignore
index c0baf81..1ccc2ba 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 .jekyll-metadata
 _site
 Gemfile.lock
+vendor
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..7d10523
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,17 @@
+before_script: "./script/bootstrap"
+script: "./script/test"
+
+#environment
+language: ruby
+rvm:
+  - 2.4.0
+
+notifications:
+  email: false
+
+env:
+  global:
+    - NOKOGIRI_USE_SYSTEM_LIBRARIES=true
+
+sudo: false
+cache: bundler
diff --git a/Gemfile b/Gemfile
index 4892c29..f50cdf4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -16,4 +16,8 @@ group :scripts do
   gem 'octokit'
 end
 
+group :test do
+  gem 'html-proofer'
+end
+
 gem 'rb-fsevent', '0.9.8' # See issue https://github.com/guard/listen/issues/431
diff --git a/_apps/settings.md b/_apps/settings.md
index 434a616..3484ab1 100644
--- a/_apps/settings.md
+++ b/_apps/settings.md
@@ -13,7 +13,7 @@ This GitHub App syncs repository settings defined in `.github/settings.yml` to G
 
 ## Usage
 
-1. **[Install the app](https://github.com/integrations/configurer/installations/new)**.
+1. **[Install the app](https://github.com/apps/settings/installations/new)**.
 2. Create a `.github/settings.yml` file in your repository. Changes to this file on the default branch will be synced to GitHub.
 
 All settings are optional.
diff --git a/_config.yml b/_config.yml
index 36065b5..aaaff4e 100644
--- a/_config.yml
+++ b/_config.yml
@@ -11,6 +11,7 @@ exclude:
   - node_modules
   - _submodules
   - script
+  - vendor
 
 sass:
   style: :compressed
@@ -35,7 +36,7 @@ defaults:
     values:
       layout: docs
 
-gems:
+plugins:
   - jekyll-octicons
   - jekyll-sitemap
   - jekyll-seo-tag
diff --git a/_layouts/app.html b/_layouts/app.html
index 4d43952..da74d47 100644
--- a/_layouts/app.html
+++ b/_layouts/app.html
@@ -10,7 +10,7 @@ layout: default
         <div class="text-gray-light">{{ page.description }}</div>
       </div>
       <div class="flex-column col-3 text-center">
-        <a class="mt-1 mb-2 d-block btn btn-primary btn-large" href="https://github.com/apps/{{ page.slug }}/installations/new">
+        <a class="mt-1 mb-2 d-block btn btn-primary btn-large" href="https://github.com/apps/{{ page.slug }}/installations/new" data-proofer-ignore>
           {% octicon plus class:"mr-2" %}
           Add to GitHub
         </a>
@@ -31,7 +31,7 @@ layout: default
             {% for screenshot in page.screenshots %}
               <input class="switcher-input" id="screenshot-{{ forloop.index }}" type="radio" name="switcher"{% if forloop.index == 1 %} checked{% endif %}>
               <div class="switcher-item content d-flex flex-items-center flex-justify-center p-3">
-                <img src="{{ screenshot }}" style="max-width:100%; max-height:100%;">
+                <img src="{{ screenshot }}" style="max-width:100%; max-height:100%;" alt="Screenshot of {{ page.title }} app">
               </div>
             {% endfor %}
           </div>
diff --git a/_layouts/docs.html b/_layouts/docs.html
index 4c4f7e0..25cbae0 100644
--- a/_layouts/docs.html
+++ b/_layouts/docs.html
@@ -34,7 +34,7 @@ layout: default
 
       <p class="alt-text-small text-gray-light">
         Find a mistake or want to help improve this documentation?
-        <a href="https://github.com/{{ site.github.repository_nwo }}/edit/{{ site.branch }}/{{ page.path }}">Suggest changes on GitHub</a>
+        <a href="https://github.com/probot/probot/edit/{{ site.branch }}/{{ page.path }}">Suggest changes on GitHub</a>
       </p>
     </div>
     <div id="toc" class="col-md-3 py-6">
diff --git a/_submodules/probot b/_submodules/probot
index 8fd40f7..f53fe41 160000
--- a/_submodules/probot
+++ b/_submodules/probot
@@ -1 +1 @@
-Subproject commit 8fd40f72c8bd5531d2ad8720ee9ea7c3d07bdf44
+Subproject commit f53fe41db559da5dcd3b2a1cd30df0bb60059b7d
diff --git a/index.html b/index.html
index f8a10e5..5c8eacf 100644
--- a/index.html
+++ b/index.html
@@ -16,7 +16,7 @@ layout: default
           </p>
         </div>
         <div class="col-3 mx-auto mx-md-0 offset-md-1 text-center text-md-right">
-          <img src="/assets/logo.png" class="width-fit">
+          <img src="/assets/logo.png" class="width-fit" alt="Probot logo">
         </div>
       </div>
     </div>
@@ -41,7 +41,7 @@ layout: default
               <div class="d-flex flex-row">
                 <div class="col-3 tooltipped tooltipped-s" aria-label="{{ app.stars }} stars">{% octicon star heigh:16 class:"v-align-middle" %} <span class="">{{ app.stars }}</span></div>
                 <div class="col-9 text-right">
-                  <img class="avatar tooltipped tooltipped-s" aria-label="Made by {{ app.author }}" height="24" src="https://github.com/{{ app.author }}.png">
+                  <img class="avatar tooltipped tooltipped-s" alt="Made by {{ app.author }}" aria-label="Made by {{ app.author }}" height="24" src="https://github.com/{{ app.author }}.png">
                 </div>
               </div>
             </div>
@@ -75,7 +75,7 @@ layout: default
 
     <div class="page-section d-flex flex-column flex-md-row gutter flex-items-center flex-md-items-center">
       <div class="col-md-6 hide-md">
-          <img src="https://assets-cdn.github.com/images/modules/site/home-illo-conversation.svg" class="d-block width-fit mx-6">
+          <img alt="" src="https://assets-cdn.github.com/images/modules/site/home-illo-conversation.svg" class="d-block width-fit mx-6">
       </div>
       <div class="col-md-6">
         <h3 class="alt-h3 mb-2">Optimized for GitHub</h3>
@@ -109,7 +109,7 @@ module.exports = robot => {
 
       <div class="d-md-flex flex-md-row flex-md-row-reverse gutter mt-4">
         <div class="col-md-6">
-          <img src="https://github.com/probot.png" height="44" width="44" class="avatar rounded-1 float-left">
+          <img alt="" src="https://github.com/probot.png" height="44" width="44" class="avatar rounded-1 float-left">
           <div class="timeline-comment box rounded-2 border bg-white" style="margin-left: 60px;">
             <div class="bg-gray px-3 py-2 border-bottom">
               <strong>@probot</strong> commented
diff --git a/script/bootstrap b/script/bootstrap
new file mode 100755
index 0000000..33a4d47
--- /dev/null
+++ b/script/bootstrap
@@ -0,0 +1,12 @@
+#!/bin/sh
+
+set -e
+export CC=gcc
+
+echo "==> Installing gem dependencies…"
+bundle check --path vendor/gems 2>&1 > /dev/null || {
+  time bundle install --binstubs bin --path vendor/gems
+}
+
+echo "==> Getting submodule for docs…"
+git submodule update --init
diff --git a/script/build b/script/build
new file mode 100755
index 0000000..2bb2977
--- /dev/null
+++ b/script/build
@@ -0,0 +1,3 @@
+#!/bin/sh
+echo "==> Building the site…"
+bundle exec jekyll build $@
diff --git a/script/html-proofer b/script/html-proofer
new file mode 100755
index 0000000..a1c4b4c
--- /dev/null
+++ b/script/html-proofer
@@ -0,0 +1,25 @@
+#!/usr/bin/env ruby
+
+require "bundler/setup"
+require "html-proofer"
+
+# add links to ignore here
+url_ignores = [
+  # Installation links require being signed in to GitHub
+  %r{https://github.com/apps/.*/installations/new},
+  "https://mochajs.org/",
+]
+
+begin
+  HTMLProofer::Runner.new(["_site"],
+    :type => :directory,
+    :url_ignore => url_ignores,
+    :file_ignore => [%r{_site/api/}],
+    :verbose => !!ENV["VERBOSE"],
+    :check_html => true,
+    :empty_alt_ignore => true
+  ).run
+rescue => e
+  puts "\n", e
+  exit 1
+end
diff --git a/script/test b/script/test
new file mode 100755
index 0000000..6a65159
--- /dev/null
+++ b/script/test
@@ -0,0 +1,6 @@
+#!/bin/sh
+
+set -e
+
+script/build
+script/html-proofer