add additional gems for prod site

Gemfile

@@ -4,4 +4,8 @@ gem 'jekyll'
 group :jekyll_plugins do
     gem 'jekyll-postcss-v2'
     gem 'jekyll-seo-tag'
+    gem 'jekyll-sitemap'
+    gem 'jekyll-feed'
+    gem 'jekyll-mentions'
+    gem 'jekyll_custom_permalink'
 end

Gemfile.lock

@@ -1,6 +1,11 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    activesupport (7.0.1)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 1.6, < 2)
+      minitest (>= 5.1)
+      tzinfo (~> 2.0)
     addressable (2.8.0)
       public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
@@ -13,6 +18,9 @@ GEM
     ffi (1.15.5)
     ffi (1.15.5-x64-mingw32)
     forwardable-extended (2.6.0)
+    html-pipeline (2.14.0)
+      activesupport (>= 2)
+      nokogiri (>= 1.4)
     http_parser.rb (0.8.0)
     i18n (1.9.0)
       concurrent-ruby (~> 1.0)
@@ -31,13 +39,21 @@ GEM
       rouge (~> 3.0)
       safe_yaml (~> 1.0)
       terminal-table (~> 2.0)
+    jekyll-feed (0.16.0)
+      jekyll (>= 3.7, < 5.0)
+    jekyll-mentions (1.6.0)
+      html-pipeline (~> 2.3)
+      jekyll (>= 3.7, < 5.0)
     jekyll-postcss-v2 (1.0.1)
     jekyll-sass-converter (2.1.0)
       sassc (> 2.0.1, < 3.0)
     jekyll-seo-tag (2.7.1)
       jekyll (>= 3.8, < 5.0)
+    jekyll-sitemap (1.4.0)
+      jekyll (>= 3.7, < 5.0)
     jekyll-watch (2.2.1)
       listen (~> 3.0)
+    jekyll_custom_permalink (0.0.1)
     kramdown (2.3.1)
       rexml
     kramdown-parser-gfm (1.1.0)
@@ -47,9 +63,17 @@ GEM
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.4.0)
+    mini_portile2 (2.7.1)
+    minitest (5.15.0)
+    nokogiri (1.13.1)
+      mini_portile2 (~> 2.7.0)
+      racc (~> 1.4)
+    nokogiri (1.13.1-x64-mingw32)
+      racc (~> 1.4)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.6)
+    racc (1.6.0)
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
@@ -62,6 +86,8 @@ GEM
       ffi (~> 1.9)
     terminal-table (2.0.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
+    tzinfo (2.0.4)
+      concurrent-ruby (~> 1.0)
     unicode-display_width (1.8.0)
 
 PLATFORMS
@@ -70,8 +96,12 @@ PLATFORMS
 
 DEPENDENCIES
   jekyll
+  jekyll-feed
+  jekyll-mentions
   jekyll-postcss-v2
   jekyll-seo-tag
+  jekyll-sitemap
+  jekyll_custom_permalink
 
 BUNDLED WITH
    2.1.4

_config.yml

@@ -16,6 +16,10 @@ url: ""
 plugins:
   - jekyll-seo-tag
   - jekyll-postcss-v2
+  - 'jekyll-sitemap'
+  - 'jekyll-feed'
+  - 'jekyll-mentions'
+  - 'jekyll_custom_permalink'
 
 exclude: [
   styles/index.css,