Implement sitemap generation (#125)

* Add sitemap generation plugin

* Exclude PDFs

Author: nanomad

Gemfile

@@ -11,4 +11,5 @@ group :jekyll_plugins do
     gem "jekyll-seo-tag"
     gem 'jekyll-default-layout'
     gem 'jekyll-include-cache'
+    gem 'jekyll-sitemap'
 end

_config.yml

@@ -32,6 +32,7 @@ plugins:
   - jekyll-last-modified-at
   - jekyll-redirect-from
   - jekyll-default-layout
+  - jekyll-sitemap
 
 color_scheme: "auto"
 enable_switch_color_scheme: true 
@@ -135,3 +136,10 @@ just_the_docs:
     sfp_cage:
       name: SFP cage
       nav_fold: true
+
+defaults:
+  -
+    scope:
+      path:            "assets/**/*.pdf"
+    values:
+      sitemap:         false