diff --git a/appengine/websockets/Gemfile.lock b/appengine/websockets/Gemfile.lock
index 190b420df..2dac62ab7 100644
--- a/appengine/websockets/Gemfile.lock
+++ b/appengine/websockets/Gemfile.lock
@@ -12,7 +12,7 @@ GEM
       rack-test (>= 0.6.3)
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
-    concurrent-ruby (1.2.2)
+    concurrent-ruby (1.3.7)
     cuprite (0.14.3)
       capybara (~> 3.0)
       ferrum (~> 0.13.0)
@@ -42,6 +42,9 @@ GEM
       rack (~> 2.2, >= 2.2.4)
     rack-test (2.1.0)
       rack (>= 1.3)
+    rackup (1.0.1)
+      rack (< 3)
+      webrick
     regexp_parser (2.8.1)
     rspec (3.12.0)
       rspec-core (~> 3.12.0)
@@ -84,6 +87,7 @@ DEPENDENCIES
   cuprite
   faye-websocket
   rack-test
+  rackup
   rspec
   rspec_junit_formatter
   sinatra