diff --git a/docker/exercises/sample_app/Gemfile.lock b/docker/exercises/sample_app/Gemfile.lock
index 02facfa..4bd3806 100644
--- a/docker/exercises/sample_app/Gemfile.lock
+++ b/docker/exercises/sample_app/Gemfile.lock
@@ -107,7 +107,9 @@ 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)
@@ -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)