diff --git a/ruby/Gemfile.lock b/ruby/Gemfile.lock
index a538ca8..4d84652 100644
--- a/ruby/Gemfile.lock
+++ b/ruby/Gemfile.lock
@@ -1,9 +1,10 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    json (2.5.1)
     mustermann (1.0.0)
     openssl (2.0.4)
-    rack (2.0.3)
+    rack (2.2.3)
     rack-protection (2.0.0)
       rack
     sinatra (2.0.0)
@@ -17,6 +18,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  json
   openssl
   sinatra