diff --git a/building-a-web-application/Gemfile.lock b/building-a-web-application/Gemfile.lock
index df7bd09..ca492d7 100644
--- a/building-a-web-application/Gemfile.lock
+++ b/building-a-web-application/Gemfile.lock
@@ -29,6 +29,7 @@ GEM
       minitest (>= 5.1)
       tzinfo (~> 2.0)
     ast (2.4.2)
+    base64 (0.2.0)
     bcrypt (3.1.19)
     concurrent-ruby (1.2.2)
     database_cleaner (2.0.1)
@@ -40,9 +41,10 @@ GEM
     diff-lcs (1.5.0)
     i18n (1.14.1)
       concurrent-ruby (~> 1.0)
+    logger (1.6.1)
     minitest (5.20.0)
     multi_json (1.15.0)
-    mustermann (3.0.0)
+    mustermann (3.0.3)
       ruby2_keywords (~> 0.0.1)
     oj (3.16.1)
     parallel (1.23.0)
@@ -53,9 +55,13 @@ GEM
     postgresql_cursor (0.6.8)
       activerecord (>= 6.0)
     racc (1.7.3)
-    rack (2.2.8.1)
-    rack-protection (3.0.4)
-      rack
+    rack (3.1.8)
+    rack-protection (4.1.0)
+      base64 (>= 0.1.0)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
     rake (13.0.6)
     rspec (3.11.0)
       rspec-core (~> 3.11.0)
@@ -71,21 +77,23 @@ GEM
       rspec-support (~> 3.11.0)
     rspec-support (3.11.1)
     ruby2_keywords (0.0.5)
-    sinatra (3.0.4)
+    sinatra (4.1.0)
+      logger (>= 1.6.0)
       mustermann (~> 3.0)
-      rack (~> 2.2, >= 2.2.4)
-      rack-protection (= 3.0.4)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.1.0)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    sinatra-contrib (3.0.4)
-      multi_json
+    sinatra-contrib (4.1.0)
+      multi_json (>= 0.0.2)
       mustermann (~> 3.0)
-      rack-protection (= 3.0.4)
-      sinatra (= 3.0.4)
+      rack-protection (= 4.1.0)
+      sinatra (= 4.1.0)
       tilt (~> 2.0)
     sinatra-flash (0.3.0)
       sinatra (>= 1.0.0)
     thread_safe (0.3.6)
-    tilt (2.2.0)
+    tilt (2.4.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
     webrick (1.8.2)