diff --git a/Gemfile.lock b/Gemfile.lock
index 73ef8ac..cdd94ba 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,8 +1,8 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.8.0)
-      public_suffix (>= 2.0.2, < 5.0)
+    addressable (2.9.0)
+      public_suffix (>= 2.0.2, < 8.0)
     colorator (1.1.0)
     concurrent-ruby (1.1.9)
     em-websocket (0.5.2)
@@ -35,6 +35,8 @@ GEM
       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)
     kramdown (2.3.1)
@@ -52,7 +54,7 @@ GEM
       jekyll-seo-tag (~> 2.1)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
-    public_suffix (4.0.6)
+    public_suffix (7.0.5)
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
@@ -73,6 +75,7 @@ PLATFORMS
 DEPENDENCIES
   jekyll (~> 4.2.0)
   jekyll-feed (~> 0.12)
+  jekyll-sitemap
   minima (~> 2.5)
   tzinfo (~> 1.2)
   tzinfo-data