diff --git a/docker/exercises/sample_app/Gemfile.lock b/docker/exercises/sample_app/Gemfile.lock
index 02facfa..4a46eb6 100644
--- a/docker/exercises/sample_app/Gemfile.lock
+++ b/docker/exercises/sample_app/Gemfile.lock
@@ -71,7 +71,7 @@ GEM
       coffee-script-source
       execjs
     coffee-script-source (1.12.2)
-    concurrent-ruby (1.0.5)
+    concurrent-ruby (1.1.10)
     connection_pool (2.2.2)
     crass (1.0.4)
     dalli (2.7.8)
@@ -82,9 +82,9 @@ GEM
     erubi (1.7.1)
     execjs (2.7.0)
     ffi (1.9.25)
-    globalid (0.4.1)
-      activesupport (>= 4.2.0)
-    i18n (1.1.0)
+    globalid (1.0.1)
+      activesupport (>= 5.0)
+    i18n (1.12.0)
       concurrent-ruby (~> 1.0)
     io-like (0.3.0)
     jbuilder (2.7.0)
@@ -107,10 +107,12 @@ GEM
       mimemagic (~> 0.3.2)
     memcachier (0.0.2)
     method_source (0.9.0)
-    mimemagic (0.3.2)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.1)
     mini_portile2 (2.3.0)
-    minitest (5.11.3)
+    minitest (5.15.0)
     msgpack (1.2.4)
     multi_json (1.13.1)
     nio4r (2.3.1)
@@ -196,7 +198,7 @@ GEM
     turbolinks (5.2.0)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
-    tzinfo (1.2.5)
+    tzinfo (1.2.10)
       thread_safe (~> 0.1)
     uglifier (4.1.18)
       execjs (>= 0.3.0, < 3)