diff --git a/Gemfile.lock b/Gemfile.lock
index 3cc0cf8..9437159 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -486,6 +486,8 @@ GEM
       coderay (~> 1.0)
       method_source (~> 0.8)
       slop (~> 3.4)
+    psych (4.0.6)
+      stringio
     public_suffix (3.1.1)
     puma (3.12.6)
     quiet_assets (1.0.2)
@@ -556,7 +558,8 @@ GEM
     rb-fsevent (0.9.4)
     rb-inotify (0.9.4)
       ffi (>= 0.5.0)
-    rdoc (6.0.4)
+    rdoc (6.4.0)
+      psych (>= 4.0.0)
     rdoc-generator-fivefish (0.4.0)
       inversion (~> 1.1)
       loggability (~> 0.12)
@@ -719,6 +722,7 @@ GEM
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
     stringex (2.5.2)
+    stringio (3.0.2)
     stripe (2.12.0)
       faraday (~> 0.9)
     stripe-ruby-mock (2.5.6)